September is one of the warmer months of the year in South Sikkim, with average highs near 24.5°C and lows around 18.5°C (mean 21.5°C). It is a relatively wet time of year, averaging 219 mm of rainfall and 88% relative humidity across the period.
September is one of the warmer months of the year in South Sikkim. Across 45 years of records, the warmest September in South Sikkim was 2024 — when the month averaged 22.7°C — while the coldest was 1984 at 20.4°C. Typical September days reach 24.5°C with nights near 18.5°C. The long-term trend is warming, about 0.2°C per decade.
September is a relatively wet time of year in South Sikkim, averaging 219 mm of rainfall. The wettest September on record was 2020 with 628 mm, while the driest was 2009 at 89 mm.
Relative humidity in South Sikkim during September averages 88%. The most humid September was 2020 at 93%, and the least humid was 1994 at 82%.
September receives about 3.9 kWh/m²/day of solar energy in South Sikkim. The sunniest September was 1997 at 4.6 kWh/m²/day, and the cloudiest were 2016 and 2020 at 3.3.
Average wind speed in South Sikkim during September is 1.1 m/s. The windiest Septembers were 2018, 2020 and 2022, among others at 1.2 m/s, while the calmest were 2010, 2013 and 2016, among others at 1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.1°C | 21.4°C | 21.4°C | 21.7°C | 22.1°C | +1°C |
| Avg High | 24.1°C | 24.6°C | 24.5°C | 24.5°C | 24.8°C | +0.7°C |
| Avg Low | 18.1°C | 18.2°C | 18.3°C | 18.9°C | 19.4°C | +1.3°C |
| Avg Rain | 194 mm | 142 mm | 170 mm | 269 mm | 383 mm | +189 mm |
September temperatures in South Sikkim have risen by about 1.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 14.6°C (1986) to a record high of 28.7°C (2024).
Rainfall in September is a relatively wet time of year, averaging 219 mm, with a wettest year of 628 mm.
A good time to visit South Sikkim
September is a good time to visit South Sikkim, with days averaging 24.5°C and nights around 18.5°C (mean 21.5°C, warmer than South Sikkim's yearly average) and higher rainfall. April and May are marginally more temperate, but September still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 25.1°C | 22.2°C | 19.3°C | 26.7°C | 17.6°C | 312 mm | 89% | 1.1 m/s | 3.8 |
| 2024 🔥 | 25.6°C | 22.7°C | 19.9°C | 28.7°C | 16.6°C | 584 mm | 88% | 1.1 m/s | 4 |
| 2023 | 24.9°C | 22.2°C | 19.5°C | 26.8°C | 17.5°C | 233 mm | 89% | 1.1 m/s | 4.2 |
| 2022 | 24.3°C | 21.7°C | 19.1°C | 25.5°C | 17.9°C | 329 mm | 92% | 1.2 m/s | 3.4 |
| 2021 | 24.6°C | 21.8°C | 19.0°C | 26.5°C | 17.5°C | 215 mm | 90% | 1.1 m/s | 4.1 |
| 2020 🌧️ | 24.3°C | 22.0°C | 19.6°C | 26.9°C | 18.6°C | 628 mm | 93% | 1.2 m/s | 3.3 |
| 2019 | 23.9°C | 21.4°C | 18.9°C | 27.4°C | 15.6°C | 344 mm | 91% | 1.1 m/s | 3.5 |
| 2018 | 25.0°C | 22.0°C | 19.0°C | 26.7°C | 18.0°C | 241 mm | 89% | 1.2 m/s | 4 |
| 2017 | 24.6°C | 22.0°C | 19.3°C | 27.4°C | 17.9°C | 197 mm | 92% | 1.2 m/s | 3.8 |
| 2016 | 23.9°C | 21.5°C | 19.1°C | 25.5°C | 17.8°C | 348 mm | 91% | 1 m/s | 3.3 |
| 2015 | 24.7°C | 22.1°C | 19.4°C | 26.4°C | 17.7°C | 257 mm | 89% | 1.1 m/s | 4 |
| 2014 | 24.5°C | 21.6°C | 18.8°C | 26.7°C | 16.7°C | 226 mm | 89% | 1.1 m/s | 3.8 |
| 2013 | 25.2°C | 22.0°C | 18.8°C | 27.1°C | 16.5°C | 193 mm | 86% | 1 m/s | 4.2 |
| 2012 | 25.1°C | 22.0°C | 18.9°C | 27.2°C | 17.8°C | 272 mm | 86% | 1.1 m/s | 3.9 |
| 2011 | 24.3°C | 21.4°C | 18.5°C | 26.5°C | 17.0°C | 284 mm | 90% | 1.2 m/s | 3.7 |
| 2010 | 24.1°C | 21.3°C | 18.4°C | 25.7°C | 17.3°C | 323 mm | 90% | 1 m/s | 3.6 |
| 2009 | 24.8°C | 21.7°C | 18.6°C | 26.4°C | 16.9°C | 89 mm | 88% | 1.1 m/s | 4.1 |
| 2008 | 24.5°C | 21.4°C | 18.2°C | 25.7°C | 17.1°C | 101 mm | 87% | 1 m/s | 3.8 |
| 2007 | 23.9°C | 21.1°C | 18.3°C | 25.9°C | 15.3°C | 281 mm | 88% | 1.1 m/s | 3.7 |
| 2006 | 24.2°C | 21.2°C | 18.3°C | 26.7°C | 16.0°C | 357 mm | 88% | 1.2 m/s | 3.9 |
| 2005 | 25.3°C | 22.1°C | 18.9°C | 26.9°C | 17.9°C | 120 mm | 85% | 1 m/s | 4.3 |
| 2004 | 24.0°C | 21.0°C | 18.1°C | 25.6°C | 15.3°C | 150 mm | 89% | 1.1 m/s | 3.6 |
| 2003 | 24.6°C | 21.6°C | 18.7°C | 26.1°C | 17.2°C | 110 mm | 89% | 1.1 m/s | 3.6 |
| 2002 | 24.8°C | 21.3°C | 17.7°C | 26.9°C | 16.2°C | 112 mm | 84% | 1.1 m/s | 3.7 |
| 2001 | 24.3°C | 21.3°C | 18.4°C | 25.9°C | 17.6°C | 200 mm | 89% | 1 m/s | 3.7 |
| 2000 | 24.2°C | 21.0°C | 17.8°C | 26.5°C | 15.4°C | 177 mm | 87% | 1.1 m/s | 3.9 |
| 1999 | 24.3°C | 21.2°C | 18.2°C | 26.0°C | 16.8°C | 122 mm | 89% | 1.1 m/s | 4.2 |
| 1998 | 24.9°C | 21.8°C | 18.6°C | 26.9°C | 17.3°C | 146 mm | 87% | 1.1 m/s | 4.2 |
| 1997 | 24.0°C | 21.0°C | 17.9°C | 26.5°C | 15.7°C | 183 mm | 89% | 1.1 m/s | 4.6 |
| 1996 | 24.7°C | 21.4°C | 18.1°C | 27.0°C | 16.2°C | 102 mm | 86% | 1 m/s | 4.5 |
| 1995 | 24.9°C | 21.6°C | 18.2°C | 27.2°C | 16.1°C | 93 mm | 86% | 1.2 m/s | 4.2 |
| 1994 | 25.5°C | 21.9°C | 18.3°C | 27.5°C | 16.6°C | 92 mm | 82% | 1.1 m/s | 4.5 |
| 1993 | 24.9°C | 21.4°C | 17.9°C | 27.9°C | 16.7°C | 102 mm | 84% | 1.2 m/s | 3.6 |
| 1992 | 24.8°C | 21.4°C | 17.9°C | 27.6°C | 15.5°C | 110 mm | 84% | 1.1 m/s | 4.3 |
| 1991 | 23.5°C | 20.9°C | 18.3°C | 25.3°C | 17.0°C | 311 mm | 92% | 1.2 m/s | 4 |
| 1990 | 24.7°C | 21.5°C | 18.3°C | 27.6°C | 16.0°C | 158 mm | 87% | 1.1 m/s | 3.6 |
| 1989 | 24.6°C | 21.5°C | 18.3°C | 27.1°C | 16.7°C | 196 mm | 88% | 1.2 m/s | 3.8 |
| 1988 | 24.9°C | 21.7°C | 18.6°C | 26.6°C | 16.6°C | 106 mm | 87% | 1.2 m/s | 3.7 |
| 1987 | 24.2°C | 21.3°C | 18.5°C | 26.2°C | 16.9°C | 236 mm | 90% | 1.1 m/s | 3.8 |
| 1986 | 23.7°C | 20.5°C | 17.3°C | 26.7°C | 14.6°C | 191 mm | 88% | 1.1 m/s | 4.1 |
| 1985 | 23.7°C | 20.8°C | 18.0°C | 26.0°C | 16.1°C | 211 mm | 89% | 1 m/s | 3.7 |
| 1984 ❄️ | 23.3°C | 20.4°C | 17.6°C | 25.9°C | 15.9°C | 278 mm | 89% | 1.2 m/s | 3.8 |
| 1983 | 24.3°C | 21.4°C | 18.5°C | 26.0°C | 17.6°C | 161 mm | 90% | 1.2 m/s | — |
| 1982 | 24.6°C | 21.3°C | 18.1°C | 26.9°C | 15.0°C | 184 mm | 87% | 1.1 m/s | — |
| 1981 | 23.8°C | 21.0°C | 18.2°C | 26.8°C | 16.6°C | 186 mm | 89% | 1 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 24.5°C with lows near 18.5°C (mean 21.5°C), based on 45 years of NASA POWER data.
September averages 219 mm of rainfall in South Sikkim, a relatively wet time of year. The wettest on record was 628 mm in 2020.
The hottest September reached 28.7°C in 2024. The coldest dipped to 14.6°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1.1°C. Daytime highs moved from 23.9°C to 24.9°C and overnight lows from 18.1°C to 19.4°C over the same span.
September is one of the warmer months of the year in South Sikkim and a relatively wet time of year, so plan for around 24.5°C daytime highs and 18.5°C at night.
Not quite — September is the 8th coolest month in South Sikkim, averaging 21.5°C.
For September in South Sikkim, pack light layers you can adjust through the day, with typical highs of 24.5°C and lows of 18.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 88% — quite humid.
Average wind speed in September is 1.1 m/s. The windiest September on record averaged 1.2 m/s (1983).
The wettest September on record was 2020 with 628 mm. On average, September sees 219 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in South Sikkim behaves each September, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for September specifically, along with year-by-year records and how the month has changed over the decades.
