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Rainfall · Tamil Nadu

Rainfall in Theni

1,105 mmof rain in an average year, 2006–2025

Theni gets 40% of its rain from the monsoon, June to September, and October is its wettest month. In 2025 it got 1,058 mm, 4% below average (normal).

Octoberwettest month, 199 mm on average
2021wettest year, 1,652 mm
2012driest year, 673 mm
9months a year with 50 mm of rain or more

Month-wise rainfall in Theni

Average rain in each month, 2006–2025.

0100200300JanJan: 19 mmFebFeb: 10 mmMarMar: 33 mmAprApr: 62 mmMayMay: 116 mmJunJun: 92 mmJulJul: 104 mmAugAug: 125 mmSepSep: 122 mmOctOct: 199 mmNovNov: 163 mmDecDec: 61 mm
MonthAverage rainShare of the year
January19 mm2%
February10 mm1%
March33 mm3%
April62 mm6%
May116 mm10%
June92 mm8%
July104 mm9%
August125 mm11%
September122 mm11%
October199 mm18%
November163 mm15%
December61 mm6%

Yearly rainfall in Theni since 2006

Lighter bars are dry years, 20% or more below average (2009, 2012, 2013, 2016), when wells and borewells are drawn hardest. The last ten years averaged 16% more rain than the ten before.

050010001500200020062006: 1,586 mm2007: 1,072 mm2008: 1,101 mm20092009: 847 mm2010: 1,145 mm2011: 902 mm20122012: 673 mm2013: 839 mm2014: 969 mm20152015: 1,116 mm2016: 674 mm2017: 1,152 mm20182018: 969 mm2019: 1,115 mm2020: 1,311 mm20212021: 1,652 mm2022: 1,462 mm2023: 1,262 mm20242024: 1,198 mm2025: 1,058 mm- - average 1,105 mm

What Theni's rain is worth to a building

Every millimetre of rain on a square metre of roof is a litre of water. A 100 m² roof in Theni sheds about 93,925 litres in an average year, most of it in a few wet months. Sent into a recharge pit, it refills the ground instead of flooding the street.

Your building: how much can you recharge?

Water you can put back each year1,87,850 L≈ 19 water tankers of 10,000 L

1 mm of rain on 1 m² is 1 litre. The surface factor allows for water lost to splash, evaporation and first-flush.

Rainwater harvesting cost in TheniGroundwater level in TheniPonds and lakes in TheniWater quality in Theni

Frequently asked questions

What is the average annual rainfall in Theni?

About 1,105 mm a year, averaged over 2006–2025 from NASA POWER satellite and weather-model data for the centre of the district. The wettest year in that time was 2021 (1,652 mm) and the driest was 2012 (673 mm).

Which month gets the most rain in Theni?

October, with 199 mm in an average year, followed by November and August. February is the driest month (10 mm).

How much of Theni's rain falls in the monsoon?

40% of a normal year's rain falls from June to September. 9 months average 50 mm or more.

How much did it rain in Theni in 2025?

1,058 mm, which is 4% below the 2006–2025 average, or "normal" in the India Meteorological Department's terms.

Is rainfall in Theni increasing or decreasing?

The last 10 years averaged 16% more rain than the 10 before them. Year-to-year swings are still bigger than that change.

How much rainwater can a house in Theni harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Theni sheds about 93,925 litres in an average year: area × rainfall × 0.85 for splash and evaporation. Sent into a recharge pit, that refills the ground under the house instead of running into the drain.

Rainfall from NASA POWER (bias-corrected satellite and weather-model rainfall) at the centre of Theni district. It reads close to, but not exactly the same as, India Meteorological Department rain-gauge totals, and rain varies within a district.

Rainfall in other districts of Tamil Nadu