Weather in Guwahati in September

The month to avoid. September is the month most people should skip in Guwahati. You should expect rain on 22 days of the month, which is more days wet than dry.

September ranks 8 of 12 in Guwahati: past the worst of the year but short of January, which is the month to book if the dates are open.

Rain on 22 of the month's 30 days, 7 of them heavy. At that frequency a wet-weather backup is not a contingency, it is the itinerary — book the indoor things first and treat the clear days as the bonus. Natural fibres and a second shirt for the day. At 85% nothing dries, including you.

What the averages hide

Averages flatten a month, and this one hides a few things: 5 days clear 35 °C, so a serious heatwave is normal rather than notable. Across the twenty years measured, the hottest September day reached 39.4 °C and the coldest night fell to 21.3 °C, and the wettest single day dropped 127 mm — roughly 56% of the month's rain in one day.

September is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest September on record still delivered 424 mm against 118 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 228 mm average is a reasonable planning figure, not a promise.

Wind is light at 1.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity at 85% is the real story though — it is the number that decides how the day feels, not the 33.1 °C.

How September sits in the year

Temperatures hold steady either side: 34.3 °C in August, 33.1 here, 31.3 in October. Nothing about the timing within the month matters much. Rain is the thing that moves: October brings 11 days less of it, so pushing the dates later buys drier weather.

Daylight in September

12.3 hours of daylight, losing 0.8 hours across the month. That is between Guwahati's extremes of 13.8 and 10.5 hours, so days are long enough not to constrain the plan.

An inland climate

Despite being inland, the year stays fairly even: 23.4 °C between the year's warmest afternoons and coldest nights.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Guwahati versus nearby

If Guwahati is one option among several, the nearby comparison is worth making. Dārjiling is a better bet in September — 13.9 °C cooler, 2 days more rain. Kolkata is close enough to be a coin toss — 2.6 °C cooler, 2 days more rain.

So: September is a compromise. January is 65 points better and is what Guwahati is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Guwahati

See all twelve months in Guwahati, or where else to go in September.