September is close to Theni's year-round average, with average highs near 28.6°C and lows around 19.5°C (mean 24.1°C). It is a relatively wet time of year, averaging 133 mm of rainfall and 80% relative humidity across the period.
September is close to Theni's year-round average. Across 45 years of records, the warmest September in Theni was 2018 — when the month averaged 25.4°C — while the coldest were 1981 and 1983 at 23°C. Typical September days reach 28.6°C with nights near 19.5°C. The long-term trend is warming, about 0.3°C per decade.
September is a relatively wet time of year in Theni, averaging 133 mm of rainfall. The wettest September on record was 1981 with 324 mm, while the driest was 2016 at 28 mm.
Relative humidity in Theni during September averages 80%. The most humid September was 1981 at 87%, and the least humid was 2012 at 71%.
September receives about 5.2 kWh/m²/day of solar energy in Theni. The sunniest September was 2002 at 6.1 kWh/m²/day, and the cloudiest was 1996 at 4.2.
Average wind speed in Theni during September is 1.7 m/s. The windiest September was 2016 at 2.2 m/s, while the calmest was 2004 at 1.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 23.6°C | 23.8°C | 24.1°C | 24.7°C | 24.3°C | +0.7°C |
| Avg High | 28.0°C | 28.3°C | 28.6°C | 29.6°C | 28.8°C | +0.8°C |
| Avg Low | 19.1°C | 19.3°C | 19.6°C | 19.8°C | 19.8°C | +0.7°C |
| Avg Rain | 166 mm | 118 mm | 139 mm | 115 mm | 125 mm | -41 mm |
September temperatures in Theni have risen by about 1°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 16.3°C (1982) to a record high of 34.4°C (2015).
Rainfall in September is a relatively wet time of year, averaging 133 mm, with a wettest year of 324 mm.
A good time to visit Theni
September is a good time to visit Theni, with days averaging 28.6°C and nights around 19.5°C (mean 24.1°C, close to Theni's yearly average) and higher rainfall. January and December 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 | 29.5°C | 25.0°C | 20.6°C | 32.6°C | 19.1°C | 127 mm | 78% | 1.8 m/s | 4.9 |
| 2024 | 29.7°C | 24.9°C | 20.1°C | 32.1°C | 18.3°C | 34 mm | 79% | 2.1 m/s | 5.5 |
| 2023 | 29.1°C | 24.4°C | 19.8°C | 31.1°C | 18.0°C | 161 mm | 79% | 1.9 m/s | 4.6 |
| 2022 | 28.2°C | 23.7°C | 19.2°C | 29.7°C | 17.9°C | 93 mm | 83% | 1.4 m/s | 5.6 |
| 2021 | 28.2°C | 24.0°C | 19.7°C | 29.9°C | 17.7°C | 191 mm | 82% | 1.8 m/s | 4.7 |
| 2020 | 28.0°C | 23.8°C | 19.7°C | 30.1°C | 18.0°C | 144 mm | 82% | 1.9 m/s | 4.3 |
| 2019 | 28.4°C | 24.2°C | 19.9°C | 30.7°C | 18.5°C | 215 mm | 81% | 1.7 m/s | 4.9 |
| 2018 🔥 | 30.8°C | 25.4°C | 20.0°C | 33.8°C | 17.8°C | 119 mm | 74% | 1.4 m/s | 5.8 |
| 2017 | 27.6°C | 23.9°C | 20.2°C | 29.6°C | 18.4°C | 201 mm | 85% | 1.4 m/s | 4.9 |
| 2016 | 30.4°C | 25.0°C | 19.5°C | 33.1°C | 17.7°C | 28 mm | 73% | 2.2 m/s | 5.6 |
| 2015 | 30.1°C | 25.3°C | 20.5°C | 34.4°C | 18.7°C | 147 mm | 76% | 1.6 m/s | 5.3 |
| 2014 | 29.2°C | 24.6°C | 20.0°C | 31.7°C | 18.3°C | 96 mm | 79% | 1.8 m/s | 5.3 |
| 2013 | 29.2°C | 24.4°C | 19.5°C | 33.4°C | 17.4°C | 67 mm | 78% | 1.9 m/s | 5 |
| 2012 | 30.9°C | 25.3°C | 19.8°C | 34.0°C | 18.8°C | 58 mm | 71% | 2 m/s | 5.5 |
| 2011 | 30.2°C | 24.8°C | 19.5°C | 33.0°C | 17.7°C | 99 mm | 74% | 2.1 m/s | 5.4 |
| 2010 | 29.1°C | 24.3°C | 19.5°C | 31.4°C | 17.9°C | 122 mm | 77% | 1.6 m/s | 5 |
| 2009 | 29.7°C | 24.9°C | 20.1°C | 33.7°C | 18.4°C | 88 mm | 77% | 2 m/s | 5 |
| 2008 | 28.9°C | 24.0°C | 19.1°C | 31.8°C | 17.0°C | 87 mm | 80% | 1.7 m/s | 5.7 |
| 2007 | 27.5°C | 23.6°C | 19.6°C | 29.2°C | 18.2°C | 140 mm | 84% | 1.9 m/s | 4.6 |
| 2006 | 27.2°C | 23.3°C | 19.5°C | 28.8°C | 17.2°C | 232 mm | 85% | 1.8 m/s | 5 |
| 2005 | 28.1°C | 23.9°C | 19.6°C | 30.7°C | 18.1°C | 154 mm | 83% | 2.1 m/s | 5.2 |
| 2004 | 27.1°C | 23.3°C | 19.6°C | 29.6°C | 18.1°C | 252 mm | 84% | 1.2 m/s | 4.9 |
| 2003 | 30.1°C | 24.8°C | 19.5°C | 31.8°C | 18.1°C | 53 mm | 77% | 1.7 m/s | 6 |
| 2002 | 30.9°C | 25.2°C | 19.4°C | 33.5°C | 17.2°C | 52 mm | 74% | 1.7 m/s | 6.1 |
| 2001 | 28.0°C | 23.9°C | 19.7°C | 31.6°C | 18.3°C | 215 mm | 82% | 1.5 m/s | 5.5 |
| 2000 | 28.0°C | 23.8°C | 19.7°C | 30.6°C | 18.6°C | 117 mm | 83% | 1.4 m/s | 5.3 |
| 1999 | 30.2°C | 25.0°C | 19.7°C | 33.0°C | 18.2°C | 32 mm | 74% | 1.7 m/s | 5.7 |
| 1998 | 26.9°C | 23.3°C | 19.6°C | 28.9°C | 18.4°C | 257 mm | 86% | 1.8 m/s | 5.2 |
| 1997 | 27.9°C | 23.7°C | 19.5°C | 30.0°C | 17.6°C | 188 mm | 84% | 1.4 m/s | 5.2 |
| 1996 | 27.2°C | 23.2°C | 19.2°C | 28.6°C | 18.3°C | 139 mm | 84% | 1.9 m/s | 4.2 |
| 1995 | 29.0°C | 24.3°C | 19.6°C | 31.9°C | 17.6°C | 78 mm | 79% | 2.1 m/s | 4.9 |
| 1994 | 27.9°C | 23.5°C | 19.0°C | 31.2°C | 16.3°C | 104 mm | 82% | 1.7 m/s | 5.1 |
| 1993 | 28.8°C | 24.0°C | 19.1°C | 31.5°C | 18.0°C | 37 mm | 77% | 1.5 m/s | 5.1 |
| 1992 | 26.9°C | 23.1°C | 19.3°C | 29.6°C | 18.0°C | 183 mm | 84% | 1.5 m/s | 4.9 |
| 1991 | 28.4°C | 23.7°C | 19.0°C | 30.3°C | 17.5°C | 85 mm | 82% | 1.4 m/s | 5.7 |
| 1990 | 29.6°C | 24.6°C | 19.5°C | 31.6°C | 18.0°C | 73 mm | 74% | 1.6 m/s | 5.2 |
| 1989 | 27.9°C | 23.6°C | 19.2°C | 30.5°C | 17.2°C | 162 mm | 82% | 1.6 m/s | 4.9 |
| 1988 | 26.7°C | 23.2°C | 19.6°C | 29.2°C | 17.9°C | 312 mm | 87% | 1.8 m/s | 4.4 |
| 1987 | 28.7°C | 24.2°C | 19.7°C | 32.1°C | 17.8°C | 93 mm | 80% | 1.4 m/s | 5.3 |
| 1986 | 29.0°C | 24.2°C | 19.4°C | 32.2°C | 18.1°C | 123 mm | 77% | 1.7 m/s | 5.1 |
| 1985 | 28.4°C | 23.6°C | 18.8°C | 32.1°C | 17.0°C | 113 mm | 79% | 1.6 m/s | 5.1 |
| 1984 | 29.2°C | 24.2°C | 19.3°C | 32.6°C | 17.2°C | 92 mm | 76% | 1.5 m/s | 5.3 |
| 1983 | 27.3°C | 23.0°C | 18.7°C | 29.1°C | 16.8°C | 241 mm | 83% | 1.8 m/s | — |
| 1982 | 28.5°C | 23.3°C | 18.2°C | 30.1°C | 16.3°C | 38 mm | 80% | 1.7 m/s | — |
| 1981 ❄️ 🌧️ | 26.6°C | 23.0°C | 19.3°C | 28.6°C | 17.8°C | 324 mm | 87% | 1.4 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 28.6°C with lows near 19.5°C (mean 24.1°C), based on 45 years of NASA POWER data.
September averages 133 mm of rainfall in Theni, a relatively wet time of year. The wettest on record was 324 mm in 1981.
The hottest September reached 34.4°C in 2015. The coldest dipped to 16.3°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 1°C. Daytime highs moved from 28°C to 28.9°C and overnight lows from 18.9°C to 19.9°C over the same span.
September is close to Theni's year-round average and a relatively wet time of year, so plan for around 28.6°C daytime highs and 19.5°C at night.
Not quite — September is the 8th coolest month in Theni, averaging 24.1°C.
For September in Theni, pack light layers you can adjust through the day, with typical highs of 28.6°C and lows of 19.5°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 80% — quite humid.
Average wind speed in September is 1.7 m/s. The windiest September on record averaged 2.2 m/s (2016).
The wettest September on record was 1981 with 324 mm. On average, September sees 133 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 Theni 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.
