September 30 closes India's southwest-monsoon rainfall accounting period. It does not mean that monsoon rain stops everywhere on that date.
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A date for counting rain
The seasonal count runs from June 1 to September 30. Using fixed dates allows the weather department to compare the same period between years.
IMD gives 868.6 millimetres as the all-India seasonal reference. The video rounds this to about 869 millimetres. This is a long-period average, meaning an average across a specified set of years.
A national average does not describe the rainfall at every town. It also differs from the normal total for only part of the season.
The September 29 comparison
The narration gives an incomplete-season comparison from September 29, 2026. IMD's final report records 759.4 millimetres against 868.6 millimetres. That gives a deficit of about 12.6 percent for the full season ending September 30.
It also describes a season below 90 percent of the long-period average as deficient. This national seasonal category differs from an individual district's rainfall category or a formal drought declaration.
The reference to 2015 compares previous low national seasons. Such comparisons need the same season, area, and reference average. An early total must not silently become a final seasonal result.
The withdrawal line
IMD confirms that withdrawal starts in western Rajasthan on September 19. Its map then shows withdrawal across the northwest while Mumbai, Kolkata, and southern regions remain outside that withdrawn area.
These are the video's dated map and forecast context. They do not describe the withdrawal line today. A withdrawal line can move as new weather observations meet IMD's criteria.
Rainfall accounting and withdrawal therefore measure different things. The count uses fixed dates; withdrawal follows changes in the circulation and moisture.
IMD's three tests
Initial withdrawal from northwest India cannot occur before September 1 under the criteria discussed. IMD looks for a combination of conditions rather than one clear afternoon.
- Check for five consecutive days without rain in the area.
- Check for a strong reduction in atmospheric moisture, including satellite evidence.
- Check for a low-level anticyclone, or high-pressure circulation.
These tests apply to the initial withdrawal in the northwest. Later withdrawal must also follow a continuous regional pattern. Applying the first area's test without its geographic scope would be misleading.
A wet final week
The video compares late-September rain with the usual amount for a short interval. Its quoted excess does not match IMD's final full-week figure. The final report gives 49 percent excess rain for the last week of September.
A wet week can reduce a seasonal deficit without removing it. The earlier months still contribute to the accumulated total. Likewise, severe rain in Uttar Pradesh can occur during a season with below-average national rain.
This explains why the national score and local flood reports can appear to conflict. They cover different areas and periods.
The next seasonal transition
Withdrawal normally reaches the whole country around mid-October, with year-to-year variation. The northeast monsoon then brings an important later rainy season to Tamil Nadu.
The transition does not happen everywhere on a single fixed day. The end of southwest-monsoon accounting is therefore not the end of every Indian rainy season.
What this means
Check what a headline means by “ends.” It may refer to the counting period, withdrawal from one region, or withdrawal from the whole country.
FAQ
Must rain stop on September 30?
No. That date ends the seasonal count.
Does a wet week prove a wet season?
No. A seasonal total includes all the earlier days in the period.
Do the five dry days apply everywhere without qualification?
No. They form part of the initial northwest-India withdrawal criteria after September 1.