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Rainfall · Sikkim

Rainfall in Mangan

773 mmof rain in an average year, 2006–2025

Mangan gets 73% of its rain from the monsoon, June to September, and July is its wettest month. In 2025 it got 947 mm, 23% above average (excess).

Julywettest month, 184 mm on average
2024wettest year, 1,197 mm
2006driest year, 452 mm
5months a year with 50 mm of rain or more

Month-wise rainfall in Mangan

Average rain in each month, 2006–2025.

050100150200JanJan: 4 mmFebFeb: 11 mmMarMar: 29 mmAprApr: 45 mmMayMay: 80 mmJunJun: 115 mmJulJul: 184 mmAugAug: 163 mmSepSep: 103 mmOctOct: 35 mmNovNov: 3 mmDecDec: 3 mm
MonthAverage rainShare of the year
January4 mm1%
February11 mm1%
March29 mm4%
April45 mm6%
May80 mm10%
June115 mm15%
July184 mm24%
August163 mm21%
September103 mm13%
October35 mm5%
November3 mm0%
December3 mm0%

Yearly rainfall in Mangan since 2006

Lighter bars are dry years, 20% or more below average (2006, 2007, 2008, 2009, 2011, 2012, 2014, 2015), when wells and borewells are drawn hardest. The last ten years averaged 79% more rain than the ten before.

05001000150020062006: 452 mm2007: 541 mm2008: 542 mm20092009: 565 mm2010: 648 mm2011: 593 mm20122012: 496 mm2013: 630 mm2014: 563 mm20152015: 515 mm2016: 933 mm2017: 856 mm20182018: 902 mm2019: 898 mm2020: 1,079 mm20212021: 1,107 mm2022: 1,064 mm2023: 939 mm20242024: 1,197 mm2025: 947 mm- - average 773 mm

What Mangan'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 Mangan sheds about 65,705 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 year1,31,410 L≈ 13 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 Mangan?

About 773 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 2024 (1,197 mm) and the driest was 2006 (452 mm).

Which month gets the most rain in Mangan?

July, with 184 mm in an average year, followed by August and June. November is the driest month (3 mm).

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

73% of a normal year's rain falls from June to September. 5 months average 50 mm or more.

How much did it rain in Mangan in 2025?

947 mm, which is 23% above the 2006–2025 average, or "excess" in the India Meteorological Department's terms.

Is rainfall in Mangan increasing or decreasing?

The last 10 years averaged 79% more rain than the 10 before them. Year-to-year swings are still bigger than that change.

How much rainwater can a house in Mangan harvest?

A 100 m² (about 1,076 sq ft) concrete roof in Mangan sheds about 65,705 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 Mangan 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 Sikkim