December is one of the cooler months of the year in Theni, with average highs near 25.8°C and lows around 16.9°C (mean 21.4°C). It is one of the drier months, averaging 57 mm of rainfall and 84% relative humidity across the period.
December is one of the cooler months of the year in Theni. Across 45 years of records, the warmest Decembers in Theni were 2012 and 2016 — when the month averaged 23.5°C — while the coldest was 1992 at 19.6°C. Typical December days reach 25.8°C with nights near 16.9°C. The long-term December temperature trend is broadly flat.
December is one of the drier months in Theni, averaging 57 mm of rainfall. The wettest December on record was 1987 with 180 mm, while the driest was 1995 at 3 mm.
Relative humidity in Theni during December averages 84%. The most humid December was 1997 at 90%, and the least humid was 2016 at 70%.
December receives about 4.6 kWh/m²/day of solar energy in Theni. The sunniest December was 1995 at 5.4 kWh/m²/day, and the cloudiest was 2020 at 3.8.
Average wind speed in Theni during December is 1.3 m/s. The windiest December was 2012 at 1.6 m/s, while the calmest was 2010 at 1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.8°C | 20.8°C | 20.8°C | 22.0°C | 21.6°C | -0.2°C |
| Avg High | 26.5°C | 25.2°C | 25.3°C | 26.6°C | 25.4°C | -1.1°C |
| Avg Low | 17.0°C | 16.4°C | 16.3°C | 17.5°C | 17.8°C | +0.8°C |
| Avg Rain | 60 mm | 61 mm | 35 mm | 45 mm | 104 mm | +44 mm |
December temperatures in Theni have stayed relatively stable across the record.
December has ranged from a record low of 11°C (1994) to a record high of 31.6°C (2016).
Rainfall in December is one of the drier months, averaging 57 mm, with a wettest year of 180 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0°C per decade while lows rose 0.3°C per decade, narrowing the gap between day and night.
One of the best times to visit Theni
December is one of the best times to visit Theni. Expect days averaging 25.8°C and nights around 16.9°C (mean 21.4°C) — cooler than Theni's yearly average — with moderate rainfall (57 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 25.4°C | 20.8°C | 16.2°C | 29.1°C | 12.9°C | 41 mm | 84% | 1.2 m/s | — |
| 2024 | 26.4°C | 22.7°C | 19.0°C | 28.7°C | 16.6°C | 147 mm | 86% | 1.1 m/s | 4.3 |
| 2023 | 25.7°C | 22.3°C | 18.9°C | 28.2°C | 16.0°C | 119 mm | 89% | 1.3 m/s | 4 |
| 2022 | 25.4°C | 21.5°C | 17.6°C | 26.9°C | 15.4°C | 101 mm | 87% | 1.2 m/s | 4.2 |
| 2021 | 25.0°C | 21.2°C | 17.3°C | 27.6°C | 13.7°C | 87 mm | 89% | 1.2 m/s | 4.9 |
| 2020 | 24.6°C | 21.1°C | 17.5°C | 25.7°C | 14.3°C | 128 mm | 90% | 1.3 m/s | 3.8 |
| 2019 | 25.3°C | 21.7°C | 18.1°C | 26.6°C | 16.7°C | 48 mm | 90% | 1.3 m/s | 4.1 |
| 2018 | 27.6°C | 22.7°C | 17.9°C | 29.8°C | 16.5°C | 13 mm | 78% | 1.1 m/s | 4.4 |
| 2017 | 25.6°C | 21.4°C | 17.1°C | 27.2°C | 12.8°C | 37 mm | 85% | 1.2 m/s | 4.8 |
| 2016 | 29.8°C | 23.5°C | 17.3°C | 31.6°C | 14.9°C | 52 mm | 70% | 1.3 m/s | 4.7 |
| 2015 | 25.2°C | 21.7°C | 18.1°C | 26.9°C | 15.2°C | 89 mm | 90% | 1.3 m/s | 4.2 |
| 2014 | 25.7°C | 21.7°C | 17.8°C | 28.7°C | 14.6°C | 34 mm | 86% | 1.3 m/s | 3.9 |
| 2013 | 27.1°C | 21.9°C | 16.7°C | 29.7°C | 13.6°C | 51 mm | 78% | 1.3 m/s | 4.5 |
| 2012 🔥 | 28.8°C | 23.5°C | 18.1°C | 31.0°C | 15.6°C | 12 mm | 75% | 1.6 m/s | 4.4 |
| 2011 | 26.3°C | 21.5°C | 16.7°C | 30.6°C | 12.9°C | 42 mm | 81% | 1.3 m/s | 4.5 |
| 2010 | 24.4°C | 20.8°C | 17.2°C | 27.2°C | 13.3°C | 75 mm | 89% | 1 m/s | 4.2 |
| 2009 | 26.3°C | 22.0°C | 17.7°C | 29.6°C | 14.4°C | 25 mm | 84% | 1.2 m/s | 4.2 |
| 2008 | 25.1°C | 20.7°C | 16.3°C | 26.2°C | 12.7°C | 21 mm | 84% | 1.3 m/s | 4.6 |
| 2007 | 25.1°C | 20.9°C | 16.8°C | 26.6°C | 13.7°C | 96 mm | 83% | 1.5 m/s | 4.4 |
| 2006 | 24.3°C | 19.9°C | 15.5°C | 26.1°C | 13.1°C | 8 mm | 88% | 1.4 m/s | 4.9 |
| 2005 | 25.0°C | 21.2°C | 17.5°C | 27.3°C | 13.7°C | 77 mm | 88% | 1.1 m/s | 4.6 |
| 2004 | 24.5°C | 19.9°C | 15.3°C | 26.0°C | 13.3°C | 9 mm | 87% | 1.3 m/s | 4.7 |
| 2003 | 25.7°C | 20.9°C | 16.0°C | 28.3°C | 12.7°C | 31 mm | 82% | 1.3 m/s | 5.1 |
| 2002 | 26.5°C | 21.3°C | 16.1°C | 28.5°C | 13.4°C | 8 mm | 78% | 1.3 m/s | 4.6 |
| 2001 | 24.5°C | 20.4°C | 16.3°C | 26.0°C | 12.7°C | 24 mm | 87% | 1.4 m/s | 4.5 |
| 2000 | 26.2°C | 20.8°C | 15.4°C | 28.4°C | 12.4°C | 51 mm | 80% | 1.4 m/s | 5 |
| 1999 | 24.6°C | 20.3°C | 16.0°C | 25.8°C | 12.2°C | 31 mm | 84% | 1.2 m/s | 4.9 |
| 1998 | 24.1°C | 20.6°C | 17.1°C | 26.2°C | 12.9°C | 147 mm | 89% | 1.3 m/s | 3.9 |
| 1997 | 25.6°C | 22.2°C | 18.9°C | 27.1°C | 15.3°C | 100 mm | 90% | 1.2 m/s | 4.2 |
| 1996 | 25.0°C | 20.6°C | 16.3°C | 29.3°C | 12.3°C | 153 mm | 85% | 1.2 m/s | 4.5 |
| 1995 | 26.6°C | 20.7°C | 14.9°C | 28.4°C | 12.9°C | 3 mm | 77% | 1.4 m/s | 5.4 |
| 1994 | 25.0°C | 19.9°C | 14.8°C | 26.7°C | 11.0°C | 12 mm | 83% | 1.3 m/s | 5.2 |
| 1993 | 24.2°C | 20.6°C | 16.9°C | 26.0°C | 13.7°C | 123 mm | 90% | 1.4 m/s | 4 |
| 1992 ❄️ | 23.8°C | 19.6°C | 15.3°C | 26.3°C | 11.6°C | 22 mm | 88% | 1.5 m/s | 4.8 |
| 1991 | 25.7°C | 21.0°C | 16.2°C | 28.9°C | 12.3°C | 16 mm | 83% | 1.3 m/s | 4.7 |
| 1990 | 27.2°C | 22.3°C | 17.5°C | 30.1°C | 14.3°C | 6 mm | 79% | 1.4 m/s | 4.7 |
| 1989 | 26.7°C | 21.6°C | 16.5°C | 29.1°C | 14.2°C | 25 mm | 80% | 1.4 m/s | 5.1 |
| 1988 | 27.3°C | 21.9°C | 16.5°C | 28.7°C | 13.2°C | 33 mm | 77% | 1.3 m/s | 5.1 |
| 1987 🌧️ | 25.0°C | 21.5°C | 18.0°C | 27.3°C | 13.1°C | 180 mm | 88% | 1.1 m/s | 4.5 |
| 1986 | 28.3°C | 23.1°C | 17.8°C | 29.9°C | 14.4°C | 23 mm | 78% | 1.4 m/s | 4.7 |
| 1985 | 27.2°C | 22.2°C | 17.2°C | 29.2°C | 14.2°C | 43 mm | 79% | 1.2 m/s | 4.9 |
| 1984 | 27.6°C | 21.8°C | 15.9°C | 30.3°C | 13.3°C | 31 mm | 72% | 1.2 m/s | 5 |
| 1983 | 25.6°C | 21.8°C | 18.1°C | 28.1°C | 15.9°C | 161 mm | 86% | 1.4 m/s | — |
| 1982 | 26.7°C | 21.7°C | 16.6°C | 28.5°C | 14.5°C | 15 mm | 79% | 1.4 m/s | — |
| 1981 | 24.2°C | 20.4°C | 16.7°C | 25.8°C | 14.1°C | 27 mm | 87% | 1.2 m/s | — |
Actual recorded December data for each year, 1981–2025 — sourced from NASA POWER.
The average high in December is around 25.8°C with lows near 16.9°C (mean 21.4°C), based on 45 years of NASA POWER data.
December averages 57 mm of rainfall in Theni, one of the drier months. The wettest on record was 180 mm in 1987.
The hottest December reached 31.6°C in 2016. The coldest dipped to 11°C in 1994.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average December temperatures have risen by about 0.1°C — but days and nights have moved in opposite directions. Overnight lows rose from 16.9°C to 17.8°C while daytime highs eased from 26.3°C to 25.6°C, narrowing the gap between day and night.
December is one of the cooler months of the year in Theni and one of the drier months, so plan for around 25.8°C daytime highs and 16.9°C at night.
Yes — December is the coldest month of the year in Theni, averaging 21.4°C.
For December in Theni, pack light layers you can adjust through the day, with typical highs of 25.8°C and lows of 16.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in December averages 84% — quite humid.
Average wind speed in December is 1.3 m/s. The windiest December on record averaged 1.6 m/s (2012).
The wettest December on record was 1987 with 180 mm. On average, December sees 57 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 December, 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 December specifically, along with year-by-year records and how the month has changed over the decades.
