Mumbai has two weather monitoring stations. One at Santacruz Airport and the other at Colaba - Navy Nagar. Since Mumbai is a coastal city, the weather is mostly humid year round. Also as it is in the tropics, it never gets very cold and the yearly extremes lie within a 30°C range.

Mumbai can be divided into 4 seasons. Winter: (December-Feb); Summer: (March-May); Monsoon (June-Sep) and withdrawal season (Oct-Dec) Here are the monthly breakup of the weather in Mumbai.

January

This is the coolest month of the year. Weather is fine. Pleasant day highs of 27° and cool nights of around 15°C. The peak low goes down to 24°/12°C, usually on the Sunday around the 15th and 18th. Chilly northern winds during the day make the city cooler than it really seems. Overall clear skies, with little smog due to the winds. The days are dry, and the nights are humid. Light mists in the morning, light fog in northern parts of the city. Deciduous trees in the city shed their leaves.

February

The fine weather continues for the first fortnight of Feb. The day highs average 29-30°C. The nights hover around 16°C. By the second fortnight the humidity starts to increase and the day temperature might rise upto 32°C. Smog increases.

March

The beginning of March sees night temperatures reach 19°C. The days reach 30-33°C. During the transition from the dry to humid weather in mid March, the temperature might hit 38-40°C. This high however, is due to hot dry winds from Gujarat. By mid March the temperatures hit 37°C, with the lows at 22°C. Humidity is unbearable, and smog affects the city. New leaves sprout from decidous trees.

April

The temperatures and humidity are still high. However the cooling effect of sea breezes makes its presence felt. The cool winds compensate for the heat. Day highs are around 35°C and lows are about 24°C. Plants are in full bloom in April.

May

Cool sea breezes cool the city, In May schools are closed for summer. Most of the residents go on a vacation to cooler hill stations or beaches. Highs of 36°C and lows of 28°C are the norm.

June

Hot weather continues. In the first week pre-Monsoon showers give some respite from the heat. The first rains however, are preceded by a strong dust storm. Monsoons hit the city on 9^th, of June, the official date. June sees a substantial amount of rainfall. At the start of the wet season, the weather is unsettled, with rain and sunshine. Temperatures are around 32°C/27°C.

July

In this month the city receives the maximum amount of rain. July and August are charaterised by almost non stop rain and weeks of no sunshine. During the peak, around late July, it may rain non stop for a week. As parts of the city are below sea level, the drains cannot flush out so much water into the sea, and those areas get flooded. The rainy season is also marks an increase in health related problems caused by water borne diseases. Atleast one cyclone hits the city annually in July/August. Highs: 31°C, Lows 25°C

August

The weather in August is almost identical to July except it has a few less rain days than July. During the wettest day, the max temperature might drop to 25°C and the night at 24°C.

September

In September the intensity of rainfall decreases. The monsoons officially end in the 3^rd week of September. September has unsettled weather. Rain does not fall continuously and are short and light. Days of sunshine also increase. Highs: 30°C. Lows 25°C.

October

In October the humidity starts to decrease and temperatures start to rise. The first week of October has pleasant highs of 30°C and lows of 24°C. The temperatures soar to a sizzing 38°C and remain above 34°C till November. The lows drop slightly to about 22°C. Smog returns to the city.

November

Hot days and warm nights occur in November. Day highs never fall below 31°C, but nights are more comfortable at 20°C. The city is very smoggy, and gets worse after Diwali, due to firecracker pollution. However the humidity is bearable.

December

The day highs hover around 31°C. The nights in the beginning of December do not fall below 18°C. By late December the day temperature ranges between 28-31. The nights may dip to 13°C in late December but average around 17°C. Humidity is low in December. Northern inland winds start to blow in December.