September is one of the warmer months of the year in East Siang, with average highs near 37.9°C and lows around 21.4°C (mean 29.7°C). It is a relatively wet time of year, averaging 349 mm of rainfall and 76% relative humidity across the period.
September is one of the warmer months of the year in East Siang. Across 45 years of records, the warmest September in East Siang was 1988 — when the month averaged 32.7°C — while the coldest were 1987 and 1997 at 27.1°C. Typical September days reach 37.9°C with nights near 21.4°C. The long-term trend is warming, about 0.3°C per decade.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 29.0°C | 29.6°C | 29.9°C | 29.5°C | 30.5°C | +1.5°C |
| Avg High | 37.6°C | 38.2°C | 38.3°C | 37.5°C | 38.1°C | +0.5°C |
| Avg Low | 20.5°C | 21.1°C | 21.4°C | 21.5°C | 22.9°C | +2.4°C |
| Avg Rain | 357 mm | 361 mm | 227 mm | 465 mm | 330 mm | -27 mm |
September temperatures in East Siang have risen by about 2.1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 18.1°C (1997) to a record high of 43.9°C (1988).
Rainfall in September is a relatively wet time of year, averaging 349 mm, with a wettest year of 757 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.1°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
A quieter season to visit East Siang
If your dates are flexible, the more temperate months of November and December tend to be the most comfortable for visiting East Siang. That said, September — with days averaging 37.9°C and nights around 21.4°C (mean 29.7°C) and higher rainfall (349 mm) — can still be rewarding for travellers who don't mind the warmth, and often means fewer crowds.
| Year | High | Low | Avg | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|
| 2025 | 38.1°C | 23.0°C | 30.5°C | 218 mm | 79% | 0.4 m/s | 4.3 |
| 2024 | 39.9°C | 23.1°C | 31.5°C | 297 mm | 73% | 0.4 m/s | 4.6 |
| 2023 | 39.1°C | 23.4°C | 31.3°C | 146 mm | 70% | 0.4 m/s | 4.5 |
| 2022 | 35.7°C | 22.5°C | 29.1°C | 454 mm | 78% | 0.4 m/s | 3.4 |
| 2021 | 39.5°C | 23.0°C | 31.3°C | 110 mm | 74% | 0.4 m/s | 4.6 |
| 2020 🌧️ | 36.4°C | 22.4°C | 29.4°C | 757 mm | 81% | 0.4 m/s | 3 |
| 2019 | 37.7°C | 18.9°C | 28.3°C | 503 mm | 81% | 0.4 m/s | 3.4 |
| 2018 | 42.2°C | 22.2°C | 32.2°C | 532 mm | 79% | 0.4 m/s | 3.4 |
| 2017 | 36.3°C | 22.4°C | 29.4°C | 399 mm | 80% | 0.4 m/s | 3.5 |
| 2016 | 35.9°C | 21.1°C | 28.5°C | 631 mm | 80% | 0.4 m/s | 3.2 |
| 2015 | 37.2°C | 22.2°C | 29.7°C | 305 mm | 80% | 0.4 m/s | 3.5 |
| 2014 | 35.5°C | 20.6°C | 28.0°C | 409 mm | 78% | 0.4 m/s | 4 |
| 2013 | 41.8°C | 21.8°C | 31.8°C | 275 mm | 79% | 0.4 m/s | 4.1 |
| 2012 | 35.6°C | 20.9°C | 28.3°C | 613 mm | 84% | 0.4 m/s | 3.5 |
| 2011 | 38.3°C | 22.4°C | 30.3°C | 383 mm | 73% | 0.4 m/s | 4.1 |
| 2010 | 34.2°C | 22.2°C | 28.2°C | 599 mm | 77% | 0.4 m/s | 3.5 |
| 2009 | 40.9°C | 22.3°C | 31.6°C | 235 mm | 71% | 0.4 m/s | 4.8 |
| 2008 | 35.9°C | 22.4°C | 29.1°C | 253 mm | 71% | 0.4 m/s | 4.2 |
| 2007 | 37.7°C | 20.5°C | 29.1°C | 317 mm | 74% | 0.4 m/s | 4.1 |
| 2006 | 37.3°C | 21.1°C | 29.2°C | 237 mm | 73% | 0.4 m/s | 3.7 |
| 2005 | 40.1°C | 22.2°C | 31.2°C | 105 mm | 69% | 0.4 m/s | 4.5 |
| 2004 | 38.9°C | 21.4°C | 30.1°C | 145 mm | 74% | 0.4 m/s | 3.9 |
| 2003 | 41.9°C | 22.8°C | 32.4°C | 266 mm | 76% | 0.4 m/s | 3.3 |
| 2002 | 37.7°C | 19.7°C | 28.7°C | 224 mm | 74% | 0.4 m/s | 3.8 |
| 2001 | 34.5°C | 22.2°C | 28.3°C | 200 mm | 72% | 0.4 m/s | 3.6 |
| 2000 | 38.4°C | 19.6°C | 29.0°C | 285 mm | 75% | 0.4 m/s | 3.5 |
| 1999 | 35.8°C | 23.4°C | 29.6°C | 180 mm | 70% | 0.4 m/s | 4.3 |
| 1998 | 42.1°C | 20.4°C | 31.3°C | 143 mm | 72% | 0.5 m/s | 4.5 |
| 1997 | 36.1°C | 18.1°C | 27.1°C | 285 mm | 78% | 0.4 m/s | 3.6 |
| 1996 | 39.2°C | 22.0°C | 30.6°C | 125 mm | 72% | 0.4 m/s | 3.6 |
| 1995 | 37.9°C | 20.7°C | 29.3°C | 564 mm | 75% | 0.4 m/s | 4 |
| 1994 | 39.8°C | 21.7°C | 30.8°C | 350 mm | 71% | 0.4 m/s | 4 |
| 1993 | 35.2°C | 20.9°C | 28.1°C | 467 mm | 75% | 0.4 m/s | 3.3 |
| 1992 | 39.9°C | 21.1°C | 30.5°C | 408 mm | 71% | 0.4 m/s | 3.6 |
| 1991 | 38.6°C | 21.3°C | 29.9°C | 440 mm | 77% | 0.4 m/s | 3.1 |
| 1990 | 37.5°C | 21.0°C | 29.2°C | 650 mm | 77% | 0.4 m/s | 2.9 |
| 1989 | 36.3°C | 21.7°C | 29.0°C | 431 mm | 77% | 0.4 m/s | 3.6 |
| 1988 🔥 | 43.9°C | 21.5°C | 32.7°C | 359 mm | 78% | 0.4 m/s | 2.5 |
| 1987 ❄️ | 34.5°C | 19.8°C | 27.1°C | 478 mm | 78% | 0.4 m/s | 2.6 |
| 1986 | 37.9°C | 20.7°C | 29.3°C | 426 mm | 77% | 0.4 m/s | 3 |
| 1985 | 35.3°C | 20.1°C | 27.7°C | 319 mm | 78% | 0.4 m/s | 3.4 |
| 1984 | 40.9°C | 18.9°C | 29.9°C | 410 mm | 76% | 0.4 m/s | 3.2 |
| 1983 | 34.8°C | 22.1°C | 28.4°C | 312 mm | 76% | 0.4 m/s | — |
| 1982 | 38.3°C | 19.4°C | 28.8°C | 264 mm | 77% | 0.4 m/s | — |
| 1981 | 36.3°C | 20.4°C | 28.4°C | 214 mm | 76% | 0.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 37.9°C with lows near 21.4°C (mean 29.7°C), based on 45 years of NASA POWER data.
September averages 349 mm of rainfall in East Siang, a relatively wet time of year. The wettest on record was 757 mm in 2020.
The hottest September reached 43.9°C in 1988. The coldest dipped to 18.1°C in 1997.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 2.1°C. Daytime highs moved from 37.1°C to 38.5°C and overnight lows from 20.2°C to 23°C over the same span.
September is one of the warmer months of the year in East Siang and a relatively wet time of year, so plan for around 37.9°C daytime highs and 21.4°C at night.
Not quite — September is the 9th coolest month in East Siang, averaging 29.7°C.
For September in East Siang, pack light, breathable clothing and sun protection, with typical highs of 37.9°C and lows of 21.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 76% — quite humid.
Average wind speed in September is 0.4 m/s. The windiest September on record averaged 0.5 m/s (1998).
The wettest September on record was 2020 with 757 mm. On average, September sees 349 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 East Siang 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.
