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Rainfall · Tamil Nadu

Rainfall in Ariyalur

1,076 mmof rain in an average year, 2006–2025

Ariyalur gets 29% of its rain from the monsoon, June to September, and November is its wettest month. In 2025 it got 1,173 mm, 9% above average (normal).

Novemberwettest month, 273 mm on average
2021wettest year, 1,653 mm
2016driest year, 642 mm
8months a year with 50 mm of rain or more

Month-wise rainfall in Ariyalur

Average rain in each month, 2006–2025.

0100200300JanJan: 32 mmFebFeb: 10 mmMarMar: 23 mmAprApr: 28 mmMayMay: 74 mmJunJun: 50 mmJulJul: 60 mmAugAug: 105 mmSepSep: 100 mmOctOct: 190 mmNovNov: 273 mmDecDec: 131 mm
MonthAverage rainShare of the year
January32 mm3%
February10 mm1%
March23 mm2%
April28 mm3%
May74 mm7%
June50 mm5%
July60 mm6%
August105 mm10%
September100 mm9%
October190 mm18%
November273 mm25%
December131 mm12%

Yearly rainfall in Ariyalur since 2006

Lighter bars are dry years, 20% or more below average (2012, 2013, 2016, 2018), when wells and borewells are drawn hardest. The last ten years averaged 8% more rain than the ten before.

050010001500200020062006: 886 mm2007: 994 mm2008: 1,262 mm20092009: 959 mm2010: 1,277 mm2011: 1,019 mm20122012: 859 mm2013: 774 mm2014: 896 mm20152015: 1,427 mm2016: 642 mm2017: 1,103 mm20182018: 849 mm2019: 1,088 mm2020: 1,209 mm20212021: 1,653 mm2022: 1,173 mm2023: 1,027 mm20242024: 1,257 mm2025: 1,173 mm- - average 1,076 mm

What Ariyalur'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 Ariyalur sheds about 91,460 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 year1,82,920 L≈ 18 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 AriyalurGroundwater level in AriyalurPonds and lakes in AriyalurWater quality in Ariyalur

Frequently asked questions

What is the average annual rainfall in Ariyalur?

About 1,076 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 (1,653 mm) and the driest was 2016 (642 mm).

Which month gets the most rain in Ariyalur?

November, with 273 mm in an average year, followed by October and December. February is the driest month (10 mm).

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

29% of a normal year's rain falls from June to September. 8 months average 50 mm or more.

How much did it rain in Ariyalur in 2025?

1,173 mm, which is 9% above the 2006–2025 average, or "normal" in the India Meteorological Department's terms.

Is rainfall in Ariyalur increasing or decreasing?

The last 10 years averaged 8% more rain than the 10 before them. Year-to-year swings are still bigger than that change.

How much rainwater can a house in Ariyalur harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Ariyalur sheds about 91,460 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 Ariyalur 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