VayuMet Meteorological Platform
An integrated multi-source weather visualisation system covering short-range forecasts, alerts seasonal outlooks, live aviation observations (METAR · TAF · SIGMET), air quality indices, agriculture weather intelligence and renewable energy resource data — all on a single interactive map.
VayuMet integrates four specialised modules into one unified experience:
Short-range GFS-based TIF rasters + vector overlays (wind barbs, contours, alerts) stepping through 41 forecast frames at 6-hour intervals.
Monthly outlooks for precipitation, temperature, and cloud cover for next six months e.g. — May through October 2026 — rendered as district and state choropleth maps.
Real-time METAR, TAF, SIGMET, PIREP, and SigWx chart overlays from the Aviation Weather Center, colour-coded by flight category. Inflight icing and turbulence forecast at critical flight levels
PM2.5, PM10, O₃, NO₂, SO₂ concentration rasters plus CPCB station live AQI points across India.
Solar irradiance (GHI, DNI, DHI), sunshine duration and wind power density at 100 m hub height — supporting site selection and generation forecasting across India.
Soil moisture, evapotranspiration, NDVI vegetation index, heat stress and growing degree days — aligned to India's Kharif and Rabi crop calendar for agri-planning support.
Main Areas
Full-screen interactive Leaflet map. Pan by dragging, zoom with scroll wheel or pinch, double-click to zoom in. Hover over features for tooltips; click for detailed popups.
Click ☰ (top-right) to open/close. Organised into sections:
- Basemap — switch between Dark, Light, Satellite, and Terrain tiles
- Forecast — all 6-hourly TIF rasters, wind, and barb layers
- Seasonal — monthly outlook layers
- Aviation — live METAR / TAF / SIGMET / SigWx
- Air Quality — pollutant rasters + live AQI stations
- Renewable — solar irradiance, solar power potential, wind power density
- Agriculture — soil moisture, soil temperature, ETP, NDVI, heat stress
- Alerts — district-level alert choropleth by day
- Live Obs — real-time weather icon stations + temperature
Appears for all animated layer types. Shows the legend colour scale, the current time label, scrubber, and playback controls. Hidden for static layers.
Displays min / max / mean statistics for the active raster layer (forecast mode), or per-day district alert counts (alert mode).
Contains the app logo, ? (this guide), and the sidebar toggle. Drag to reposition if needed.
The timeline is context-sensitive — it automatically adapts to the active layer type:
| Mode | Period | Interval | Label format |
|---|---|---|---|
| Forecast (TIF/wind/barb) | 10 days | 6 hours | Mon DD HH:00 UTC |
| Alerts | 10 days | 1 day | Day +1 … Day +5 |
| Seasonal | 6 months | 1 month | Six months e.g. May 2026 … Oct 2026 |
Playback Controls
Step one frame backward or forward. Buttons grey out at the first/last frame.
Auto-advance at ~1 frame/second. Click again to pause. Loops back to frame 0 when it reaches the end.
Drag the range slider directly to any frame. Tick marks beneath show hourly or day labels.
The legend strip sits at the top of the timeline bar, immediately above the scrubber. It shows:
- A horizontal colour-ramp bar spanning the full data range for the active layer
- Numeric tick labels beneath (low on left → high on right)
- The physical unit to the right of the bar (e.g.
mm,°C,m/s,µg/m³)
Example: Precipitation (mm)
0 → light blue → deep blue → violet (heavy rain, >100 mm)
Example: Temperature (°C)
Cold blue → neutral yellow → hot red
| Layer | Unit | Description |
|---|---|---|
| Precipitation | mm / 6 h | GFS total precipitation accumulation per 6-hour step. Includes rainfall and equivalent liquid snowfall. |
| Snowfall | cm / 6 h | Equivalent snow depth accumulation. Visible mainly over Himalayas and northern plains in winter. |
| Humidity | % | 2-metre relative humidity (surface level). Values > 85% indicate fog or heavy rain risk. |
| Layer | Unit | Description |
|---|---|---|
| Total Cloud | % | Vertically integrated cloud fraction at any altitude (0–100%). Indicates general overcast conditions. |
| Low Cloud | % | Cloud fraction below ~2 km. Dense low cloud (>80%) often associated with fog or stratus. |
| Mid Cloud | % | Cloud fraction 2–6 km. Altocumulus, altostratus. |
| High Cloud | % | Cloud fraction above 6 km. Cirrus and cirrostratus; thin ice crystal clouds. |
Wind Animation (Surface)
Particle-based streamline animation (leaflet-velocity) showing 10-metre wind direction and speed. Brighter/faster particles = stronger wind. The animation runs continuously at the selected time step.
Wind Barbs (Pressure Levels)
Wind barbs are classic meteorological symbols showing speed and direction simultaneously:
- The staff points in the direction from which wind blows (INTO the station)
- Each full barb = 10 knots
- Each half barb = 5 knots
- A pennant (filled triangle) = 50 knots
| Layer | Pressure | Approx. altitude |
|---|---|---|
| Barbs 850 hPa | 850 hPa | ~1,500 m (low troposphere) |
| Barbs 500 hPa | 500 hPa | ~5,500 m (middle troposphere) |
| Barbs 300 hPa | 300 hPa | ~9,000 m (jet stream level) |
| Wind Tendency 24h | Surface | Change in wind vector over 24 hours |
Wind Speed Rasters
Colour-coded wind speed at surface (10 m), 850 hPa, 500 hPa, and 300 hPa levels in m/s.
| Layer | Unit | Description |
|---|---|---|
| Temperature 2m | °C | Air temperature at 2 metres above ground level (near-surface, feels-like proxy). |
| Max Temperature | °C | Maximum 2m temperature within the 6-hour window. Useful for heat wave monitoring. |
| Min Temperature | °C | Minimum 2m temperature within the 6-hour window. Key for frost/cold-wave alerts. |
| Dew Point | °C | Temperature at which air becomes saturated. Dew point ≥ 26°C is uncomfortably humid. |
| Temperature 850 hPa | °C | Free-atmosphere temperature at ~1,500 m. Used in thunderstorm stability analysis. |
| Temperature 500 hPa | °C | Mid-troposphere temperature; negative values indicate active weather systems. |
Flight Categories (colour code used throughout)
METAR Stations
METAR (Meteorological Aerodrome Report) dots are placed at each reporting airport. Click any dot to expand its decoded observation in a popup.
The coloured ring around each dot reflects the current flight category at that station.
METAR sub-layers
| Sub-layer | What it shows |
|---|---|
| Wx Icons | Weather symbol (rain, snow, fog, thunderstorm) at each station instead of a plain dot. |
| Temperature | Current OAT/dew-point label in °C at each station. |
| Visibility | Reported visibility in metres (or km). Colour: grey >8 km, green 3–8 km, yellow 1–3 km, orange 500–1,000 m, red <500 m. |
TAF Forecast
TAF (Terminal Aerodrome Forecast) dots share the same locations as METARs. Each dot colour reflects the worst flight category in the next 24-hour forecast window.
Click a TAF dot to open a time-series chart showing forecast ceiling (ft AGL), visibility (sm), wind speed (kt), and gusts for each forecast period.
SIGMET
SIGMET (Significant Meteorological Information) polygons highlight airspace affected by:
- Thunderstorm / convective activity
- Severe or extreme turbulence
- Severe icing
- Tropical cyclones
- Volcanic ash clouds
Hover for the full SIGMET text; colour indicates hazard type.
PIREP (Pilot Reports)
Pilot reports plotted as small aircraft icons at the position and altitude they were observed. Hover to see reported turbulence intensity, icing type, and sky conditions.
SigWx Chart
The international Significant Weather (SigWx) chart is rendered as a transparent overlay using decoded weather symbols (thunderstorm, icing, turbulence, jet-stream lines) at the reported position and flight level.
Seasonal layers display NCEP CFSv2 monthly outlooks as district-level choropleth maps covering the southwest and northeast monsoon seasons (May–October 2026).
Layer Grid (3 × 2)
| Anomaly | Forecast value | |
|---|---|---|
| 🌧 Precip | % departure from normal | mm per month |
| 🌡 Temp | °C departure from normal | °C (monthly mean) |
| ☁ Cloud | % departure from normal | % cloud fraction |
Anomaly vs. Forecast
- Anomaly (Anom) — departure from the climatological normal. Positive = above average; negative = below average. Useful for identifying unusual months.
- Forecast (Fc) — the actual predicted value. Useful for absolute planning (e.g., how many mm of rain expected).
District Time-Series Panel
Click any district on a seasonal layer to open the side panel showing a 6-month bar + line chart for the selected variable. The blue bars show the forecast value; the amber line shows the anomaly. Switch between Precip / Temp / Cloud using the buttons at the top of the panel.
Raster Layers
| Layer | Unit | Source | Notes |
|---|---|---|---|
| PM2.5 | µg/m³ | ECMWF-CAMS | Fine particulate ≤ 2.5 µm. Major health hazard. NAAQS limit: 60 µg/m³ 24h avg. |
| PM10 | µg/m³ | ECMWF-CAMS | Coarse dust particles ≤ 10 µm. Often elevated during dust storms. |
| Ozone (O₃) | µg/m³ | ECMWF-CAMS | Ground-level ozone formed from NOₓ + VOC + sunlight. High in summer afternoons (In Future). |
| NO₂ | µg/m³ | ECMWF-CAMS | Nitrogen dioxide. Peaks near urban centres and highways.(In Future) |
| SO₂ | µg/m³ | ECMWF-CAMS | Sulfur dioxide. Elevated near coal-fired power plants and industrial zones.(In Future) |
Live AQI Stations
CPCB/SAFAR monitoring stations displayed as coloured circles using the National AQI scale (To be added in Future):
| AQI Range | Category | Colour |
|---|---|---|
| 0 – 50 | Good | ● Green |
| 51 – 100 | Satisfactory | ● Light Green |
| 101 – 200 | Moderate | ● Yellow |
| 201 – 300 | Poor | ● Orange |
| 301 – 400 | Very Poor | ● Red |
| 401 – 500 | Severe | ● Dark Red/Maroon |
VayuMet's renewable energy layers are sourced from NOAA GFS and provide forecast-driven resource assessment data at ~25 km resolution — updated four times daily. They are designed to support site selection, generation forecasting and grid planning for India's rapidly expanding solar and wind energy sectors.
Solar Irradiance Layers
| Layer | Unit | Description & Use |
|---|---|---|
| Global Horizontal Irradiance (GHI) | W/m² | Total downward solar radiation on a horizontal surface — the primary metric for flat-panel (PV) solar yield assessment. High over Rajasthan, Gujarat, and the Deccan plateau year-round. |
| Direct Normal Irradiance (DNI) | W/m² | Direct beam radiation on a surface perpendicular to the sun — key for Concentrated Solar Power (CSP) plants and high-efficiency tracked PV. Best in arid northwest India. |
| Diffuse Horizontal Irradiance (DHI) | W/m² | Sky-scattered radiation. Higher in cloudy/monsoon conditions. Formula: GHI = DNI × cos(θ) + DHI. Important for yield estimation in cloudy coastal regions. |
| Sunshine Duration | hours/day | Number of hours with direct insolation exceeding 120 W/m². Rajasthan and Gujarat average 8–10 h/day in summer; Kerala and Assam drop to 3–5 h/day during monsoon months. |
Wind Energy Layers
| Layer | Unit | Description & Use |
|---|---|---|
| Wind Power Density (100 m) | W/m² | Available kinetic energy flux at hub height (~100 m AGL). IEC Class 3 (≥300 W/m²) is the commercial viability threshold. Excellent in Jaisalmer/Barmer (Rajasthan), Kutch (Gujarat) and Tamil Nadu coastal belt. |
| Wind Speed at 100 m | m/s | Mean hub-height wind speed extracted from GFS. Use with the animated wind layer (select 100 m level) for directional patterns. Persistent south-westerlies during monsoon are a key resource window. |
India's Key Renewable Energy Zones
GHI exceeds 6.0 kWh/m²/day in summer. Thar Desert has India's highest DNI — optimal for both PV and CSP. Use the GHI layer to compare day-to-day cloud impact during monsoon.
Andhra Pradesh, Telangana, Karnataka — second-highest solar potential in India. GHI 5.5–6.0 kWh/m²/day. Check cloud cover layer alongside GHI for day-ahead generation forecasting.
India's premier wind energy zone. Wind Power Density layer shows Class 5–6 sites (≥400 W/m²). Use the 100 m animated wind layer to identify diurnal wind maxima.
Consistent south-westerlies during summer monsoon. Use the 850 hPa wind layer alongside the 100 m layer to understand the low-level jet contribution to coastal wind resource.
India's agricultural economy is deeply dependent on the behaviour of the southwest monsoon (June–September) for the Kharif crop season, and on winter western disturbances and temperature patterns for the Rabi crop season (October–March). VayuMet's agro-meteorological layers give farmers, agri-planners and researchers the weather intelligence to make informed decisions across the crop calendar.
Agro-Meteorological Layer Reference
| Layer | Unit | Description & Crop Significance |
|---|---|---|
| Soil Moisture | m³/m³ | Volumetric water content in the top 10 cm soil layer. Values >0.35 indicate near-saturation; <0.10 is the wilting-point threshold for most crops. Critical for sowing readiness — rice and cotton require soil moisture >0.25 before transplanting/direct sowing. |
| Evapotranspiration (ETP) | mm/day | Combined soil evaporation and plant transpiration. Daily ETP drives irrigation water demand — if precipitation < ETP for consecutive days, irrigation is required. Peak ETP (8–10 mm/day) occurs in May–June pre-monsoon over northwest India. |
| NDVI | Index (−1 to +1) | Normalised Difference Vegetation Index from MODIS/Sentinel composites. NDVI >0.4 indicates healthy dense canopy; 0.2–0.4 sparse/stressed crop; <0.2 bare/severely stressed. Use to assess drought impact or monitor crop progress across districts. |
| Heat Stress Index | °C | Combined temperature + humidity stress indicator. Critical above 32°C for most Kharif crops (paddy, soybean, groundnut) and above 28°C for wheat during grain filling. Pre-monsoon heat stress (May) is particularly damaging for summer vegetables. |
| Growing Degree Days (GDD) | GDD | Accumulated thermal units above the crop's base temperature (typically 10°C for wheat; 8°C for maize). Tracks crop phenology — flowering, grain filling, maturity. Useful for forecasting harvest timing and scheduling post-harvest operations. |
| Min Temperature (2m) | °C | Minimum surface temperature. Frost risk threshold for Rabi crops: <2°C for wheat, <5°C for mustard/vegetables. Use the Min Temperature layer in November–February to monitor cold wave and frost risk across IGP (Indo-Gangetic Plains). |
Seasonal Agriculture Guidance
Monitor the Soil Moisture layer alongside the Precipitation forecast. Sowing window opens when soil moisture exceeds 0.20 m³/m³ after the first significant monsoon spell (≥25 mm in 3 days). Check the CFSv2 Seasonal layer for district-level monsoon outlook.
Use the Precipitation cumulative layer to track deficit or excess over the week. Combine with NDVI composites (updated weekly) to assess crop vigour. Districts with persistently below-normal NDVI and below-normal CFSv2 precipitation anomaly signal drought stress.
Unseasonal rainfall during harvest severely damages paddy, soybean and cotton. Monitor the 7-day Precipitation forecast carefully from mid-October. Use the Cloud Cover layer to identify dry windows for mechanised harvesting.
Wheat sowing requires soil temperature 20–22°C and soil moisture >0.15. Use the Temperature 2m and Soil Moisture layers to identify the optimal sowing window. Western disturbances from November onward provide supplemental moisture for Rabi crops in north India.
Use the Min Temperature layer with the IMD Alerts cold-wave overlay for advance warning. Frost at <2°C for 2+ consecutive nights causes irreversible damage to wheat, mustard and vegetables. Monitor districts in Rajasthan, UP, Punjab, and Haryana most closely.
The Heat Stress Index and Max Temperature layers are most critical in May–June for summer vegetables and fruit orchards. Mango flowering (Feb–Mar) is particularly sensitive to temperature anomalies — use the Temperature 850 hPa layer to track synoptic-scale heat build-up.
- Open the Seasonal → Precip Anomaly layer for your district to check if 2026 seasonal outlook is normal/below-normal.
- Switch to Forecast → Precipitation and step through the 7-day frames to identify the first significant rainfall event (≥25 mm).
- After the event, check Soil Moisture — if >0.20 m³/m³, conditions are ready for sowing.
- Confirm with Precipitation Day 3–5 frames that a dry window follows (no immediate waterlogging risk).
IMD district alert choropleth maps shaded by the highest severity colour issued for each district. The timeline scrubber moves between Day +1 (tomorrow) and Day +5.
IMD Colour Code System
| Colour | Meaning | Action suggested |
|---|---|---|
| Green | No warning — conditions normal | No action required |
| Yellow | Watch — severe weather possible | Be aware; monitor updates |
| Orange | Alert — severe weather likely | Be prepared; take precautions |
| Red | Warning — extreme weather imminent | Take action; avoid exposure |
Bottom-Left Stats
While an alert layer is active, the floating stats panel shows the district counts for each colour category on the selected day — e.g., "Red: 12 | Orange: 34 | Yellow: 67".
| Sub-layer | What is shown |
|---|---|
| Wx Icons | Present-weather symbol (rain, fog, snow, thunderstorm, haze …) at each SYNOP / METAR station. Based on the WMO ww code. |
| Temperature | 2m air temperature in °C overlaid as a label at each station. Colour-coded cold (blue) → hot (red). |
| Source | Layers | Resolution | Update |
|---|---|---|---|
| NCEP GFS National Centers for Environmental Prediction — Global Forecast System |
Precipitation, Wind, Temp, Cloud, Humidity, Agriculture | 0.25° | 4× daily (00/06/12/18 UTC) |
| NCEP CFSv2 Climate Forecast System v2 — Seasonal model |
Seasonal Precip / Temp / Cloud anomalies and forecasts | 1.0° (district aggregate) | Monthly |
| FAA / AWC Aviation Weather Center |
METAR, TAF, SIGMET, PIREP, SigWx | Station-based | Real-time (METAR: ~1 h) |
| NCEP GFS National Centers for Environmental Prediction — Global Forecast System |
District colour-code weather alerts | District polygon | Daily |
| ECMWF-CAMS CAMS global atmospheric composition forecasts |
Air pollution data PM2.5, PM10, AOD, Dust-AOD | 0.25° | Daily |
| MODIS / Sentinel (Not yet added) NASA / ESA |
NDVI | 250 m – 10 m | Weekly composite |
| Term | Definition |
|---|---|
| METAR | Meteorological Aerodrome Report — hourly surface observation from airports in standardised format. |
| TAF | Terminal Aerodrome Forecast — 24/30 h airport weather forecast issued by aviation met offices. |
| SIGMET | Significant Meteorological Information — advisory for hazardous en-route weather affecting a defined airspace block. |
| PIREP | Pilot Report — airborne observation of actual weather conditions (turbulence, icing, clouds). |
| SigWx | Significant Weather Chart — international graphic chart showing upper-level hazards for flight planning. |
| VFR / IFR | Visual / Instrument Flight Rules — defines minimum visibility/ceiling for different flight categories. |
| GHI | Global Horizontal Irradiance — total downward solar radiation on a horizontal plane (W/m²). Primary metric for flat-panel solar yield assessment. |
| DNI | Direct Normal Irradiance — direct beam solar radiation on a surface perpendicular to the sun. Key metric for CSP (Concentrated Solar Power) plants. |
| ETP | Evapotranspiration — combined water loss from soil surface evaporation and plant transpiration. Drives irrigation demand calculation. |
| NDVI | Normalised Difference Vegetation Index — satellite-derived greenness proxy for crop health monitoring. Values >0.4 indicate healthy dense canopy. |
| GDD | Growing Degree Days — heat accumulation above a crop's base temperature (typically 10°C). Tracks crop phenology from sowing to harvest. |
| Kharif | India's summer crop season — sown at monsoon onset (June–July), harvested October–November. Major crops: rice, cotton, soybean, groundnut, maize. |
| Rabi | India's winter crop season — sown October–November, harvested March–April. Major crops: wheat, mustard, chickpea, barley. |
| LPA | Long Period Average — the 50-year (1971–2020) climatological mean rainfall for India (88 cm), used as the baseline for seasonal anomaly forecasts. |
| AQI | Air Quality Index — composite index (0–500) aggregating multiple pollutant concentrations into a single health metric. |
| Anomaly | Departure from the long-term climatological mean, expressed as absolute units or percentage. |
| GDD | Growing Degree Days — heat accumulation above a base temperature that drives crop development. |
| hPa | Hectopascal — pressure unit. 1 hPa = 1 mbar. Standard atmosphere = 1013.25 hPa at sea level. |
| UTC | Coordinated Universal Time. IST = UTC + 5:30. All forecast valid times are in UTC. |
| CFSv2 | Climate Forecast System version 2 — NCEP coupled ocean-atmosphere-land model used for seasonal outlooks. |
Keyboard Shortcuts
| Key | Action |
|---|---|
| ← / → | Step back / forward one frame (click scrubber first to focus it) |
| Space | Play / Pause animation (when scrubber is focused) |
| + / − | Zoom map in / out |
| Esc | Close open popups and side panels |
Workflow Tips
Activate a wind speed raster (e.g. Wind 850 hPa), then click a wind barb layer (Barbs 850 hPa). Both render simultaneously — colour shows magnitude, barbs show direction.
Check the Precip Anomaly layer first to identify which districts are forecast above/below normal, then switch to Precip Forecast for absolute millimetres.
METAR shows now; TAF shows the next 24 h. For flight planning, start with TAF flight categories, then click a dot for the detailed ECharts period chart.
Most layers show rich tooltips on hover without needing a click. Reserve clicks for the detailed side panels (TAF chart, seasonal district chart).
The forecast frame labels (e.g. "Mon 12 06:00 UTC") are in UTC. Add 5 h 30 min for Indian Standard Time (IST).
Activate GHI first, note peak irradiance zones. Then switch to Total Cloud Cover — high cloud fraction (>70%) over GHI hotspots forecasts generation loss. Step through the 7-day timeline to identify clear-sky windows for best output days.
Step the Precipitation layer to find the first ≥25 mm event in your district. Then check Soil Moisture — if it rises above 0.20 m³/m³ and the next 3-day forecast stays dry, the sowing window is open. Cross-reference with Seasonal → Precip Anomaly to understand the broader season outlook.
Performance Notes
- TIF rasters are decoded in the browser using GeoTIFF.js — the first load per layer takes 1–3 seconds; subsequent steps use a pre-fetched cache.
- Aviation layers make live AWC API calls — response time depends on your network.
- Seasonal data is pre-fetched in the background for all 6 months once you activate the first month; subsequent steps load instantly.
- Wind particle animation is GPU-accelerated via canvas; lowering your browser zoom helps on slower machines.