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Rainfall · Tamil Nadu

Rainfall in Namakkal

824 mmof rain in an average year, 2006–2025

Namakkal gets 39% of its rain from the monsoon, June to September, and October is its wettest month. In 2025 it got 708 mm, 14% below average (normal).

Octoberwettest month, 152 mm on average
2021wettest year, 1,210 mm
2016driest year, 410 mm
8months a year with 50 mm of rain or more

Month-wise rainfall in Namakkal

Average rain in each month, 2006–2025.

050100150200JanJan: 11 mmFebFeb: 5 mmMarMar: 20 mmAprApr: 37 mmMayMay: 96 mmJunJun: 54 mmJulJul: 64 mmAugAug: 100 mmSepSep: 105 mmOctOct: 152 mmNovNov: 127 mmDecDec: 52 mm
MonthAverage rainShare of the year
January11 mm1%
February5 mm1%
March20 mm2%
April37 mm4%
May96 mm12%
June54 mm7%
July64 mm8%
August100 mm12%
September105 mm13%
October152 mm18%
November127 mm15%
December52 mm6%

Yearly rainfall in Namakkal since 2006

Lighter bars are dry years, 20% or more below average (2009, 2016), when wells and borewells are drawn hardest.

05001000150020062006: 754 mm2007: 844 mm2008: 1,083 mm20092009: 641 mm2010: 1,061 mm2011: 860 mm20122012: 739 mm2013: 680 mm2014: 667 mm20152015: 870 mm2016: 410 mm2017: 812 mm20182018: 666 mm2019: 837 mm2020: 825 mm20212021: 1,210 mm2022: 1,031 mm2023: 733 mm20242024: 1,044 mm2025: 708 mm- - average 824 mm

What Namakkal'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 Namakkal sheds about 70,040 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 year1,40,080 L≈ 14 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 NamakkalGroundwater level in NamakkalPonds and lakes in NamakkalWater quality in Namakkal

Frequently asked questions

What is the average annual rainfall in Namakkal?

About 824 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 (1,210 mm) and the driest was 2016 (410 mm).

Which month gets the most rain in Namakkal?

October, with 152 mm in an average year, followed by November and September. February is the driest month (5 mm).

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

39% of a normal year's rain falls from June to September. 8 months average 50 mm or more.

How much did it rain in Namakkal in 2025?

708 mm, which is 14% below the 2006–2025 average, or "normal" in the India Meteorological Department's terms.

Is rainfall in Namakkal increasing or decreasing?

It has held roughly steady: the last 10 years averaged within 5% of the 10 before them. Year-to-year swings are much bigger than the trend.

How much rainwater can a house in Namakkal harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Namakkal sheds about 70,040 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 Namakkal 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