The climate of Mumbai is an extreme version of a tropical wet and dry climate with a lengthy, practically rainless dry season and a relatively short, but extremely rainy wet season due to the Southwest Monsoon and orographic influences from the nearby Western Ghats. Some suburbs (e.g. Santacruz) are sufficiently wet to qualify as a tropical monsoon climate. Mumbai's climate can be best described as moderately hot with a high level of humidity. Its coastal nature and tropical location ensure temperatures do not fluctuate much throughout the year.
The mean annual temperature is . Average annual rainfall is in Colaba, which represents South Mumbai and in Santacruz, which represents central and suburban Mumbai. The mean maximum average temperatures is about in summer and in winter, while the average minimums are in summer and in winter.
Climate Change
As climate change and global warming are issues of rapidly increasing importance, the Mumbai Government launched the Mumbai Climate Action Plan to tackle climate change and extreme weather events.
Climate data for Mumbai
Sea temperature
Monthly breakdown of climate
The following is the monthly breakdown of the weather in Mumbai.
January
January is the coolest month of the year for Mumbai with mean daily minimum being 16.4 °C and mean daily maximum being 30.1 °C. The nightly lows may vary between 13 °C and 20 °C. Chilly northern winds during the day make the city seem cooler than it really is. Generally clear skies, with some smog – especially in the early morning – are the norm. The days are dry, the nights relatively humid. January is also associated with the deciduous trees in the city shedding their leaves. 26–27 January 2008 recorded a maximum temperature of 10.2 °C, which is the lowest recorded in 45 years. The lowest recorded temperature is 7.4 °C (45.3 °F) on 22 January 1962 which was the coldest day in Mumbai. Coastal areas are relatively cooler during the day, but they are warmer at night.
February
The fine January weather continues for the first fortnight of February. The mean daily minimum stays at 17.3 °C and mean daily maximum being 31.3 °C with some possibility of unseasonable showers. Smog increases. 6 February 2008 recorded a minimum temperature of 9.4 °C. Just two days later, on 8 February, the minimum temperature recorded was 8.5 °C, which was the lowest temperature Mumbai has seen since January 1962.
March
The month of March sees a mean minimum temp of 20.6 °C and mean maximum temp of 32.7 °C. During the transition from the dry to humid weather in mid March, the temperature might hit 38 to 40 °C. This high however, is due to hot dry winds from Gujarat. By mid-March the temperatures may hit 37 °C, with the lows at 24 °C. Humidity is unbearable, and smog affects the city. New leaves sprout from deciduous trees. The all-time high day temperature for March was recorded in 2018 at 41.7 °C.
April
The temperatures and humidity are still high. However, the cooling effect of the sea breezes makes its presence felt. The high temperature stays around 35.1 °C and daily lows are around 23.2 °C. Plants are in full bloom in April.
May
May is the hottest month of the year for Mumbai with the cool sea breezes providing some relief. The daily maximum hovers around 34.5 °C and the daily low is 29.1 °C.
June
June marks the beginning of the monsoon period in Mumbai. The beginning of the month is characterized by a continuation of the summer with increased humidity. The official date for the monsoon to hit the city is 10 June. This period is marked by thunderstorms and often windy conditions as the monsoon establishes itself over the city. Rainfall activity intensifies as the month goes on, leading into wettest month, July. The max and min mean daily temperatures are measured at 31.9 °C/26.6 °C.
July
In this month the city receives the maximum amount of rain. July and August are characterized by almost non-stop rain and weeks of no sunshine. A continuous monsoon current covers the entire western coast of India during this period. Rainfall activity is less stormy and more constant with a relatively constant breeze from the West or South West. It is not uncommon for parts of the city to be waterlogged during periods of persistent heavy rain. This affects the city's public transport system often leading to long delays. During periods of severe precipitation, the city's commuter rail system is often suspended because of water logging and poor visibility.