NCDEX rainfall futures · Cumulative Deviation
Rainfall RAINCHNNAI As on Wednesday, September 02, 2026 09:30 AM · RAINMUMBAI As on Wednesday, September 02, 2026 10:34 AM · page generated 02 Sep 2026 13:24 IST
What these indices are. Each one settles on how far a city's rainfall runs
above or below normal. The index opens on day one of the season at the whole
season's normal — 2,206.7 mm for Mumbai, 998.25 mm for Chennai
— then each day adds the actual rainfall at that city's two IMD observatories
and subtracts the normal for that date. Rising means wetter than normal; falling
means drier. One millimetre is worth Rs 50 per lot on both, so either panel can
be read in rupees as well as rainfall.
Between them the two contracts cover June to December: Mumbai
runs the southwest monsoon from 1 June to 30 September, Chennai the northeast
monsoon from 1 September to 31 December. They overlap only in September. The two
are shown on separate axes on purpose — their starting points differ by more
than a factor of two, and so does how far each typically travels in a season, so a
shared scale would flatten one and mislead on both.
RAINCHNNAI ·
Chennai · northeast monsoonlive day 2 of 122
Official spot
990mm
02 Sep · Rs 49,522/lot
vs anchor
-8mm
deficit
Model spread
34mm
at 16 Sep · Rs 1,698/lot
Season rank
0th pct
of 5 seasons on this date
2026 official spotVM-AIFS projectionVM-IFS projection5-season median10th–90th percentile
13:16
Date
Lead
VM-AIFS mm
VM-IFS mm
LPA
VM-AIFS CDR
VM-IFS CDR
Gap
02 Sep
1
2.3
2.6
993
03 Sep
1
3.6
3.8
4.2
992
990
+2
04 Sep
2
3.9
14.9
7.2
989
998
-9
05 Sep
3
3.5
1.1
4.3
988
995
-7
06 Sep
4
3.7
12.7
3.4
988
1,004
-15
07 Sep
5
4.2
0.6
2.9
990
1,002
-12
08 Sep
6
5.1
15.8
3.8
991
1,014
-23
09 Sep
7
3.0
4.1
3.2
991
1,014
-24
10 Sep
8
2.4
4.9
5.2
988
1,014
-26
11 Sep
9
2.4
1.1
8.7
982
1,006
-25
12 Sep
10
2.6
2.2
4.7
980
1,004
-24
13 Sep
11
3.5
1.0
2.8
980
1,002
-22
14 Sep
12
3.6
1.3
4.2
980
999
-20
15 Sep
13
2.7
15.5
5.5
977
1,009
-33
16 Sep
14
2.2
3.6
4.0
975
1,009
-34
Where the two sources diverge, that gap is the honest
uncertainty — and it is wider than either model's own error statistics
imply. Both under-forecast heavy rain badly, so treat any active spell in these
trajectories as a lower bound.
Contract
Last
vs spot
As of
Front month · LTP
948.00-1
-42.5
13:16 live
2026-09-29(Sep Fut)
949.00
-41.5*
01 Sep
2026-10-30(Oct Fut)
949.00
-41.5*
01 Sep
2026-11-27(Nov Fut)
949.00
-41.5*
01 Sep
2026-12-30(Dec Fut)
949.00
-41.5*
01 Sep
* these are the last daily futures prints and they predate the current spot, so that column compares two different days. The exchange's series feed carries one value per calendar day and publishes the current day's only once it settles. The front-month row above is the live last-traded price and is the one to read intraday.
RAINMUMBAI ·
Mumbai · southwest monsoonlive day 94 of 122
Official spot
2,335mm
02 Sep · Rs 116,750/lot
vs anchor
+128mm
excess
Model spread
10mm
at 16 Sep · Rs 506/lot
Season rank
20th pct
of 5 seasons on this date
2026 official spotVM-AIFS projectionVM-IFS projection5-season median10th–90th percentile
13:16
Date
Lead
VM-AIFS mm
VM-IFS mm
LPA
VM-AIFS CDR
VM-IFS CDR
Gap
02 Sep
1
4.6
13.2
18.4
2,321
2,330
-9
03 Sep
1
6.8
10.1
17.4
2,311
2,322
-12
04 Sep
2
5.5
11.8
17.7
2,298
2,317
-18
05 Sep
3
5.2
10.6
12.9
2,290
2,314
-24
06 Sep
4
4.4
11.1
9.4
2,285
2,316
-30
07 Sep
5
3.0
7.9
7.3
2,281
2,316
-35
08 Sep
6
3.1
7.7
8.4
2,276
2,316
-40
09 Sep
7
3.1
8.5
9.8
2,269
2,314
-45
10 Sep
8
3.2
7.0
13.6
2,259
2,308
-49
11 Sep
9
3.3
8.1
11.3
2,251
2,305
-54
12 Sep
10
2.2
8.7
8.9
2,244
2,304
-60
13 Sep
11
6.8
10.3
11.1
2,240
2,304
-64
14 Sep
12
41.8
18.7
9.7
2,272
2,313
-41
15 Sep
13
44.7
23.1
10.8
2,306
2,325
-19
16 Sep
14
29.8
20.7
8.2
2,327
2,338
-10
Where the two sources diverge, that gap is the honest
uncertainty — and it is wider than either model's own error statistics
imply. Both under-forecast heavy rain badly, so treat any active spell in these
trajectories as a lower bound.
Contract
Last
vs spot
As of
Front month · LTP
2,086.00-12
-249.0
13:16 live
2026-06-29(Jun Fut)
2,096.00
-239.0*
30 Jun
2026-07-30(Jul Fut)
2,635.00
+300.0*
31 Jul
2026-08-28(Aug Fut)
2,389.00
+54.0*
31 Aug
2026-09-29(Sep Fut)
2,098.00
-237.0*
01 Sep
* these are the last daily futures prints and they predate the current spot, so that column compares two different days. The exchange's series feed carries one value per calendar day and publishes the current day's only once it settles. The front-month row above is the live last-traded price and is the one to read intraday.
Verification — out of sample, RAINCHNNAI, RAINMUMBAI
How each model has actually performed once the real rainfall
was published. Bias is the average miss and its sign shows the direction
— positive means too wet. MAE is the typical miss ignoring direction;
lower is better on both.
Basis
Model
Lead
n
Bias
MAE
RMSE
Chennai
AIFS
D+1
2
+2.33
2.33
2.33
Chennai
IFS
D+1
1
+4.94
4.94
4.94
Mumbai
AIFS
D+1
8
-1.90
5.53
7.34
Mumbai
AIFS
D+2
5
-1.17
4.85
6.46
Mumbai
AIFS
D+3
4
+1.84
2.85
2.92
Mumbai
AIFS
D+4
4
-1.91
5.42
6.88
Mumbai
AIFS
D+5
3
+1.77
2.96
3.08
Mumbai
IFS
D+1
7
+3.29
6.98
7.35
Mumbai
IFS
D+2
5
+6.80
6.80
7.22
Mumbai
IFS
D+3
5
+3.60
6.40
6.78
Mumbai
IFS
D+4
4
+4.66
5.49
6.25
Mumbai
IFS
D+5
3
+5.58
5.58
5.86
6 settlement day(s) scored against the official spot.
Below about 30 days this is provisional, not a track record. Scores belong to the
basis they were measured on and do not transfer: the northeast monsoon is a
different forecast problem from the southwest, so a Mumbai track record says
nothing about Chennai skill.