September is one of the cooler months of the year in Idukki, with average highs near 25.4°C and lows around 20°C (mean 22.7°C). It is a relatively wet time of year, averaging 208 mm of rainfall and 91% relative humidity across the period.
September is one of the cooler months of the year in Idukki. Across 45 years of records, the warmest Septembers in Idukki were 2015 and 2024 — when the month averaged 23.4°C — while the coldest was 1983 at 21.8°C. Typical September days reach 25.4°C with nights near 20°C. The long-term trend is warming, about 0.2°C per decade.
September is a relatively wet time of year in Idukki, averaging 208 mm of rainfall. The wettest September on record was 1988 with 511 mm, while the driest was 1999 at 35 mm.
Relative humidity in Idukki during September averages 91%. The most humid September was 1998 at 93%, and the least humid was 1999 at 88%.
September receives about 5.2 kWh/m²/day of solar energy in Idukki. The sunniest September was 2002 at 6.1 kWh/m²/day, and the cloudiest was 1996 at 4.2.
Average wind speed in Idukki during September is 0.5 m/s. The windiest Septembers were 1988 and 1998 at 0.6 m/s, while the calmest were 2019, 2022 and 2023, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.4°C | 22.5°C | 22.8°C | 22.9°C | 23.0°C | +0.6°C |
| Avg High | 25.1°C | 25.2°C | 25.5°C | 25.6°C | 25.5°C | +0.4°C |
| Avg Low | 19.6°C | 19.9°C | 20.1°C | 20.1°C | 20.4°C | +0.8°C |
| Avg Rain | 207 mm | 174 mm | 233 mm | 201 mm | 234 mm | +27 mm |
September temperatures in Idukki have risen by about 0.8°C between 1981–1985 and 2021–2025.
September has ranged from a record low of 16.9°C (2016) to a record high of 29.6°C (2002).
Rainfall in September is a relatively wet time of year, averaging 208 mm, with a wettest year of 511 mm.
A good time to visit Idukki
September is a good time to visit Idukki, with days averaging 25.4°C and nights around 20°C (mean 22.7°C, close to Idukki'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 | 25.7°C | 23.3°C | 21.0°C | 27.7°C | 20.3°C | 185 mm | 91% | 0.5 m/s | 4.9 |
| 2024 | 26.0°C | 23.4°C | 20.9°C | 28.0°C | 20.2°C | 113 mm | 91% | 0.5 m/s | 5.5 |
| 2023 | 25.6°C | 22.9°C | 20.2°C | 28.0°C | 18.8°C | 347 mm | 90% | 0.4 m/s | 4.6 |
| 2022 | 25.6°C | 22.8°C | 19.9°C | 27.6°C | 19.3°C | 151 mm | 91% | 0.4 m/s | 5.6 |
| 2021 | 25.4°C | 22.9°C | 20.3°C | 27.5°C | 19.4°C | 266 mm | 92% | 0.5 m/s | 4.7 |
| 2020 | 25.0°C | 22.6°C | 20.1°C | 27.8°C | 18.5°C | 342 mm | 92% | 0.5 m/s | 4.3 |
| 2019 | 25.3°C | 22.8°C | 20.2°C | 27.9°C | 18.2°C | 358 mm | 92% | 0.4 m/s | 4.9 |
| 2018 | 26.5°C | 23.2°C | 19.9°C | 29.0°C | 18.4°C | 125 mm | 89% | 0.4 m/s | 5.8 |
| 2017 | 25.7°C | 23.1°C | 20.6°C | 28.0°C | 19.8°C | 340 mm | 92% | 0.5 m/s | 4.9 |
| 2016 | 25.5°C | 22.7°C | 19.9°C | 26.6°C | 16.9°C | 44 mm | 89% | 0.5 m/s | 5.6 |
| 2015 🔥 | 26.2°C | 23.4°C | 20.5°C | 28.9°C | 19.1°C | 214 mm | 90% | 0.4 m/s | 5.3 |
| 2014 | 25.6°C | 23.0°C | 20.5°C | 28.5°C | 19.4°C | 182 mm | 91% | 0.5 m/s | 5.3 |
| 2013 | 25.2°C | 22.6°C | 20.0°C | 27.7°C | 18.8°C | 150 mm | 91% | 0.5 m/s | 5 |
| 2012 | 25.6°C | 22.8°C | 19.9°C | 27.9°C | 18.7°C | 126 mm | 89% | 0.5 m/s | 5.5 |
| 2011 | 25.0°C | 22.4°C | 19.7°C | 27.1°C | 17.3°C | 220 mm | 91% | 0.5 m/s | 5.4 |
| 2010 | 25.4°C | 22.6°C | 19.8°C | 27.9°C | 18.9°C | 251 mm | 91% | 0.4 m/s | 5 |
| 2009 | 25.3°C | 22.8°C | 20.2°C | 28.4°C | 18.8°C | 231 mm | 91% | 0.5 m/s | 5 |
| 2008 | 25.6°C | 22.7°C | 19.7°C | 27.5°C | 17.7°C | 258 mm | 90% | 0.5 m/s | 5.7 |
| 2007 | 24.7°C | 22.4°C | 20.1°C | 28.4°C | 18.6°C | 413 mm | 93% | 0.5 m/s | 4.6 |
| 2006 | 24.8°C | 22.4°C | 20.1°C | 27.8°C | 18.5°C | 389 mm | 92% | 0.5 m/s | 5 |
| 2005 | 25.1°C | 22.7°C | 20.4°C | 26.9°C | 19.6°C | 274 mm | 92% | 0.5 m/s | 5.2 |
| 2004 | 25.2°C | 22.4°C | 19.7°C | 26.9°C | 18.0°C | 242 mm | 91% | 0.4 m/s | 4.9 |
| 2003 | 26.3°C | 23.3°C | 20.3°C | 28.7°C | 19.6°C | 48 mm | 89% | 0.5 m/s | 6 |
| 2002 | 26.4°C | 23.2°C | 19.9°C | 29.6°C | 18.6°C | 110 mm | 88% | 0.5 m/s | 6.1 |
| 2001 | 25.5°C | 22.8°C | 20.1°C | 27.9°C | 19.1°C | 252 mm | 90% | 0.5 m/s | 5.5 |
| 2000 | 25.7°C | 22.9°C | 20.1°C | 28.0°C | 19.3°C | 111 mm | 90% | 0.4 m/s | 5.3 |
| 1999 | 26.1°C | 23.0°C | 20.0°C | 27.8°C | 18.6°C | 35 mm | 88% | 0.4 m/s | 5.7 |
| 1998 | 24.2°C | 22.2°C | 20.2°C | 26.3°C | 18.9°C | 428 mm | 93% | 0.6 m/s | 5.2 |
| 1997 | 25.5°C | 22.7°C | 20.0°C | 27.1°C | 19.5°C | 321 mm | 91% | 0.4 m/s | 5.2 |
| 1996 | 24.3°C | 21.9°C | 19.6°C | 25.9°C | 18.5°C | 251 mm | 92% | 0.5 m/s | 4.2 |
| 1995 | 25.1°C | 22.6°C | 20.2°C | 26.9°C | 18.8°C | 170 mm | 91% | 0.5 m/s | 4.9 |
| 1994 | 25.2°C | 22.4°C | 19.7°C | 28.8°C | 18.1°C | 151 mm | 91% | 0.5 m/s | 5.1 |
| 1993 | 25.3°C | 22.4°C | 19.6°C | 27.1°C | 18.7°C | 46 mm | 89% | 0.4 m/s | 5.1 |
| 1992 | 24.5°C | 22.1°C | 19.8°C | 26.3°C | 18.0°C | 248 mm | 92% | 0.5 m/s | 4.9 |
| 1991 | 26.1°C | 23.0°C | 19.9°C | 27.8°C | 19.0°C | 42 mm | 89% | 0.5 m/s | 5.7 |
| 1990 | 25.4°C | 22.5°C | 19.6°C | 27.7°C | 17.8°C | 49 mm | 88% | 0.5 m/s | 5.2 |
| 1989 | 24.9°C | 22.2°C | 19.6°C | 26.3°C | 17.7°C | 204 mm | 91% | 0.5 m/s | 4.9 |
| 1988 🌧️ | 24.5°C | 22.3°C | 20.1°C | 26.1°C | 18.6°C | 511 mm | 93% | 0.6 m/s | 4.4 |
| 1987 | 25.7°C | 22.9°C | 20.1°C | 27.9°C | 18.5°C | 97 mm | 90% | 0.5 m/s | 5.3 |
| 1986 | 25.3°C | 22.5°C | 19.7°C | 26.7°C | 18.9°C | 154 mm | 89% | 0.5 m/s | 5.1 |
| 1985 | 25.1°C | 22.2°C | 19.2°C | 27.6°C | 17.9°C | 102 mm | 89% | 0.4 m/s | 5.1 |
| 1984 | 25.7°C | 22.5°C | 19.4°C | 28.0°C | 18.2°C | 102 mm | 89% | 0.5 m/s | 5.3 |
| 1983 ❄️ | 24.3°C | 21.8°C | 19.4°C | 26.3°C | 17.7°C | 249 mm | 91% | 0.5 m/s | — |
| 1982 | 25.6°C | 22.5°C | 19.4°C | 27.2°C | 18.6°C | 50 mm | 89% | 0.4 m/s | — |
| 1981 | 24.6°C | 22.3°C | 19.9°C | 26.5°C | 18.9°C | 398 mm | 93% | 0.5 m/s | — |
Actual recorded September data for each year, 1981–2025 — sourced from NASA POWER.
The average high in September is around 25.4°C with lows near 20°C (mean 22.7°C), based on 45 years of NASA POWER data.
September averages 208 mm of rainfall in Idukki, a relatively wet time of year. The wettest on record was 511 mm in 1988.
The hottest September reached 29.6°C in 2002. The coldest dipped to 16.9°C in 2016.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average September temperatures have risen by about 0.8°C. Daytime highs moved from 25.1°C to 25.7°C and overnight lows from 19.5°C to 20.5°C over the same span.
September is one of the cooler months of the year in Idukki and a relatively wet time of year, so plan for around 25.4°C daytime highs and 20°C at night.
Not quite — September is the 6th coolest month in Idukki, averaging 22.7°C.
For September in Idukki, pack light layers you can adjust through the day, with typical highs of 25.4°C and lows of 20°C. Bring an umbrella or light rain jacket too.
Relative humidity in September averages 91% — quite humid.
Average wind speed in September is 0.5 m/s. The windiest September on record averaged 0.6 m/s (1988).
The wettest September on record was 1988 with 511 mm. On average, September sees 208 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 Idukki 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.
