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Rainfall · Bihar

Rainfall in Gaya

1,121 mmof rain in an average year, 2006–2025

Gaya gets 84% of its rain from the monsoon, June to September, and July is its wettest month. In 2025 it got 1,404 mm, 25% above average (excess).

Julywettest month, 291 mm on average
2021wettest year, 1,509 mm
2022driest year, 746 mm
6months a year with 50 mm of rain or more

Month-wise rainfall in Gaya

Average rain in each month, 2006–2025.

0100200300400JanJan: 12 mmFebFeb: 14 mmMarMar: 15 mmAprApr: 14 mmMayMay: 54 mmJunJun: 167 mmJulJul: 291 mmAugAug: 275 mmSepSep: 205 mmOctOct: 64 mmNovNov: 4 mmDecDec: 6 mm
MonthAverage rainShare of the year
January12 mm1%
February14 mm1%
March15 mm1%
April14 mm1%
May54 mm5%
June167 mm15%
July291 mm26%
August275 mm25%
September205 mm18%
October64 mm6%
November4 mm0%
December6 mm1%

Yearly rainfall in Gaya since 2006

Lighter bars are dry years, 20% or more below average (2009, 2010, 2018, 2022, 2023), when wells and borewells are drawn hardest.

050010001500200020062006: 1,190 mm2007: 1,222 mm2008: 1,249 mm20092009: 872 mm2010: 780 mm2011: 1,239 mm20122012: 1,173 mm2013: 1,066 mm2014: 1,103 mm20152015: 1,165 mm2016: 1,319 mm2017: 1,117 mm20182018: 881 mm2019: 1,106 mm2020: 1,369 mm20212021: 1,509 mm2022: 746 mm2023: 868 mm20242024: 1,045 mm2025: 1,404 mm- - average 1,121 mm

What Gaya'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 Gaya sheds about 95,285 litres in an average year, most of it in four monsoon 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 year1,90,570 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.

Frequently asked questions

What is the average annual rainfall in Gaya?

About 1,121 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 (1,509 mm) and the driest was 2022 (746 mm).

Which month gets the most rain in Gaya?

July, with 291 mm in an average year, followed by August and September. November is the driest month (4 mm).

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

84% of a normal year's rain falls from June to September. 6 months average 50 mm or more.

How much did it rain in Gaya in 2025?

1,404 mm, which is 25% above the 2006–2025 average, or "excess" in the India Meteorological Department's terms.

Is rainfall in Gaya 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 Gaya harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Gaya sheds about 95,285 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 Gaya 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 Bihar