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Rainfall · Tamil Nadu

Rainfall in Tiruvannamalai

961 mmof rain in an average year, 2006–2025

Tiruvannamalai gets 48% of its rain from the monsoon, June to September, and October is its wettest month. In 2025 it got 946 mm, 2% below average (normal).

Octoberwettest month, 149 mm on average
2021wettest year, 1,417 mm
2016driest year, 622 mm
8months a year with 50 mm of rain or more

Month-wise rainfall in Tiruvannamalai

Average rain in each month, 2006–2025.

050100150200JanJan: 9 mmFebFeb: 5 mmMarMar: 18 mmAprApr: 36 mmMayMay: 102 mmJunJun: 78 mmJulJul: 99 mmAugAug: 141 mmSepSep: 141 mmOctOct: 149 mmNovNov: 132 mmDecDec: 52 mm
MonthAverage rainShare of the year
January9 mm1%
February5 mm1%
March18 mm2%
April36 mm4%
May102 mm11%
June78 mm8%
July99 mm10%
August141 mm15%
September141 mm15%
October149 mm16%
November132 mm14%
December52 mm5%

Yearly rainfall in Tiruvannamalai since 2006

Lighter bars are dry years, 20% or more below average (2012, 2014, 2016, 2018), when wells and borewells are drawn hardest. The last ten years averaged 10% more rain than the ten before.

05001000150020062006: 772 mm2007: 1,076 mm2008: 1,210 mm20092009: 851 mm2010: 1,090 mm2011: 792 mm20122012: 674 mm2013: 858 mm2014: 675 mm20152015: 1,136 mm2016: 622 mm2017: 1,016 mm20182018: 630 mm2019: 930 mm2020: 1,132 mm20212021: 1,417 mm2022: 1,320 mm2023: 908 mm20242024: 1,165 mm2025: 946 mm- - average 961 mm

What Tiruvannamalai'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 Tiruvannamalai sheds about 81,685 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 year1,63,370 L≈ 16 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 TiruvannamalaiGroundwater level in TiruvannamalaiPonds and lakes in Tiruvannamalai

Frequently asked questions

What is the average annual rainfall in Tiruvannamalai?

About 961 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 (1,417 mm) and the driest was 2016 (622 mm).

Which month gets the most rain in Tiruvannamalai?

October, with 149 mm in an average year, followed by August and September. February is the driest month (5 mm).

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

48% of a normal year's rain falls from June to September. 8 months average 50 mm or more.

How much did it rain in Tiruvannamalai in 2025?

946 mm, which is 2% below the 2006–2025 average, or "normal" in the India Meteorological Department's terms.

Is rainfall in Tiruvannamalai increasing or decreasing?

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

How much rainwater can a house in Tiruvannamalai harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Tiruvannamalai sheds about 81,685 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 Tiruvannamalai 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