August is one of the warmer months of the year in Siwan, with average highs near 35.1°C and lows around 24.7°C (mean 29.9°C). It is a relatively wet time of year, averaging 245 mm of rainfall and 83% relative humidity across the period.
August is one of the warmer months of the year in Siwan. Across 45 years of records, the warmest August in Siwan was 1983 — when the month averaged 31.5°C — while the coldest was 2008 at 28.7°C. Typical August days reach 35.1°C with nights near 24.7°C. The long-term August temperature trend is broadly flat.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 29.8°C | 29.7°C | 29.8°C | 30.1°C | 30.1°C | +0.3°C |
| Avg High | 35.1°C | 35.0°C | 35.1°C | 35.2°C | 35.3°C | +0.2°C |
| Avg Low | 24.5°C | 24.5°C | 24.6°C | 25.0°C | 25.0°C | +0.5°C |
| Avg Rain | 259 mm | 256 mm | 252 mm | 228 mm | 224 mm | -35 mm |
August temperatures in Siwan have stayed relatively stable across the record.
August has ranged from a record low of 23.4°C (1993) to a record high of 38.1°C (2009).
Rainfall in August is a relatively wet time of year, averaging 245 mm, with a wettest year of 453 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0°C per decade while lows rose 0.2°C per decade, narrowing the gap between day and night.
A quieter season to visit Siwan
If your dates are flexible, the more temperate months of November and February tend to be the most comfortable for visiting Siwan. That said, August — with days averaging 35.1°C and nights around 24.7°C (mean 29.9°C) and higher rainfall (245 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 | 35.2°C | 25.1°C | 30.1°C | 245 mm | 86% | 2.3 m/s | 4.1 |
| 2024 | 34.8°C | 25.2°C | 30.0°C | 230 mm | 83% | 2 m/s | 4.5 |
| 2023 | 37.1°C | 24.9°C | 31.0°C | 261 mm | 81% | 2.6 m/s | 3.9 |
| 2022 | 37.6°C | 24.9°C | 31.2°C | 156 mm | 76% | 2.6 m/s | 5 |
| 2021 | 33.4°C | 25.5°C | 29.4°C | 317 mm | 88% | 2.1 m/s | 3.7 |
| 2020 | 33.7°C | 24.2°C | 29.0°C | 133 mm | 87% | 2.3 m/s | 5 |
| 2019 | 35.3°C | 25.6°C | 30.4°C | 113 mm | 83% | 2.2 m/s | 5.1 |
| 2018 | 34.2°C | 25.7°C | 29.9°C | 191 mm | 83% | 1.8 m/s | 4.4 |
| 2017 | 34.7°C | 25.0°C | 29.9°C | 286 mm | 87% | 2 m/s | 4.2 |
| 2016 | 36.1°C | 25.4°C | 30.7°C | 121 mm | 79% | 2.4 m/s | 5.4 |
| 2015 | 35.2°C | 24.8°C | 30.0°C | 274 mm | 83% | 1.8 m/s | 4.8 |
| 2014 | 35.8°C | 24.9°C | 30.3°C | 350 mm | 81% | 2 m/s | 4.5 |
| 2013 | 36.4°C | 24.4°C | 30.4°C | 200 mm | 76% | 1.8 m/s | 5 |
| 2012 | 34.0°C | 24.5°C | 29.3°C | 251 mm | 83% | 1.7 m/s | 4.9 |
| 2011 | 34.0°C | 24.5°C | 29.3°C | 243 mm | 86% | 2.3 m/s | 4.6 |
| 2010 | 36.4°C | 25.3°C | 30.8°C | 251 mm | 81% | 2 m/s | 4.9 |
| 2009 | 38.1°C | 24.8°C | 31.4°C | 297 mm | 81% | 2.1 m/s | 4.4 |
| 2008 ❄️ | 33.3°C | 24.1°C | 28.7°C | 428 mm | 89% | 2.2 m/s | 4.8 |
| 2007 | 35.1°C | 24.0°C | 29.5°C | 300 mm | 87% | 1.8 m/s | 4.6 |
| 2006 | 34.5°C | 24.8°C | 29.6°C | 229 mm | 83% | 2.5 m/s | 5.4 |
| 2005 | 34.4°C | 24.3°C | 29.3°C | 234 mm | 84% | 2 m/s | 4.5 |
| 2004 | 34.0°C | 25.4°C | 29.7°C | 238 mm | 84% | 2.8 m/s | 5.3 |
| 2003 | 34.5°C | 25.2°C | 29.9°C | 164 mm | 85% | 2.2 m/s | 5 |
| 2002 | 36.3°C | 24.0°C | 30.1°C | 190 mm | 82% | 2.7 m/s | 5.2 |
| 2001 | 35.5°C | 25.0°C | 30.2°C | 196 mm | 81% | 1.9 m/s | 5.1 |
| 2000 | 34.8°C | 24.8°C | 29.8°C | 240 mm | 83% | 2.1 m/s | 4.9 |
| 1999 | 34.3°C | 24.5°C | 29.4°C | 186 mm | 84% | 2.1 m/s | 4.4 |
| 1998 | 33.7°C | 25.0°C | 29.3°C | 319 mm | 87% | 1.9 m/s | 4.3 |
| 1997 | 34.3°C | 24.6°C | 29.4°C | 261 mm | 87% | 2.5 m/s | 4.7 |
| 1996 | 33.7°C | 23.8°C | 28.8°C | 329 mm | 88% | 2.1 m/s | 5.3 |
| 1995 | 33.0°C | 25.1°C | 29.0°C | 270 mm | 86% | 2.4 m/s | 5.5 |
| 1994 | 37.3°C | 25.0°C | 31.1°C | 289 mm | 82% | 2.4 m/s | 5.1 |
| 1993 | 38.0°C | 23.4°C | 30.7°C | 262 mm | 72% | 2.1 m/s | 4.5 |
| 1992 | 35.2°C | 24.0°C | 29.6°C | 256 mm | 82% | 2.5 m/s | 5.2 |
| 1991 | 35.9°C | 25.0°C | 30.5°C | 255 mm | 81% | 2.6 m/s | 3.8 |
| 1990 | 34.2°C | 24.7°C | 29.4°C | 136 mm | 89% | 2.5 m/s | 5.4 |
| 1989 | 34.8°C | 23.5°C | 29.1°C | 147 mm | 82% | 2.4 m/s | 5.2 |
| 1988 | 34.4°C | 24.4°C | 29.4°C | 436 mm | 87% | 2.3 m/s | 4 |
| 1987 🌧️ | 34.5°C | 24.1°C | 29.3°C | 453 mm | 87% | 2.4 m/s | 4.5 |
| 1986 | 34.5°C | 23.6°C | 29.1°C | 219 mm | 83% | 2.4 m/s | 5.4 |
| 1985 | 34.7°C | 25.0°C | 29.8°C | 288 mm | 85% | 2.2 m/s | 5.2 |
| 1984 | 34.4°C | 24.9°C | 29.6°C | 242 mm | 85% | 2.6 m/s | 5.7 |
| 1983 🔥 | 37.6°C | 25.4°C | 31.5°C | 128 mm | 74% | 2.7 m/s | — |
| 1982 | 36.6°C | 25.3°C | 30.9°C | 199 mm | 77% | 2.8 m/s | — |
| 1981 | 34.1°C | 24.2°C | 29.1°C | 221 mm | 88% | 2.4 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 35.1°C with lows near 24.7°C (mean 29.9°C), based on 45 years of NASA POWER data.
August averages 245 mm of rainfall in Siwan, a relatively wet time of year. The wettest on record was 453 mm in 1987.
The hottest August reached 38.1°C in 2009. The coldest dipped to 23.4°C in 1993.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.1°C. Daytime highs moved from 35.5°C to 35.6°C and overnight lows from 25°C to 25.1°C over the same span.
August is one of the warmer months of the year in Siwan and a relatively wet time of year, so plan for around 35.1°C daytime highs and 24.7°C at night.
Not quite — August is the 8th coolest month in Siwan, averaging 29.9°C.
For August in Siwan, pack light, breathable clothing and sun protection, with typical highs of 35.1°C and lows of 24.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 83% — quite humid.
Average wind speed in August is 2.3 m/s. The windiest August on record averaged 2.8 m/s (1982).
The wettest August on record was 1987 with 453 mm. On average, August sees 245 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 Siwan behaves each August, 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 August specifically, along with year-by-year records and how the month has changed over the decades.
