The climate of West Bengal is varied, with tropical savannahs in the southern portions of the state, to humid subtropical areas in the north. Temperatures vary widely, and there are five distinct seasons. The area is vulnerable to heavy rainfall, monsoons, and cyclones. There are some mountains in the area which are generally cold all year round.
There are five main seasons in West Bengal: spring, summer, rainy season, a short autumn, and winter.
Spring is considered the most pleasant season over the plains of West Bengal and lies from mid-February to mid-March and is also the time where Holi is celebrated. Temperatures range between 20 °C – 30 °C and no rainfall. Though occasional rain or light showers are witnessed due to Western disturbances in North India.
The summer season is observed from March to May in most of Bengal.
In Bengal, summers can be extremely hot and have high humidity. The plains of South Bengal have a daily maximum temperature around 35–38 °C.[1] [2] It can also exceed 40 °C.[3] [4] [5] [6] [7] The western highlands experience a dry summer like northern India. During the day, the temperature ranges from 38 to 42 °C, though it can reach or exceed 45 °C.[8] [9] [10] [11] [12] In summer, the plains of North Bengal are generally cooler than the west and south.[13] [14] [15] In this area, the daily maximum temperature varies from 26 to 32 °C.[16] It occasionally crosses 35 °C. The minimum temperature in summer is approximately 18–22 °C.The Darjeeling hill region is the coolest area in summer. Here, the daily highest temperature is 15–25 °C.
| City | Average temperature (°C) | Average Rainfall (mm) | |
|---|---|---|---|
| 13.1 | 446 | ||
| 24.2 | 447 | ||
| 24.0 | 453 | ||
| 28.3 | 188 | ||
| 29.4 | 264 | ||
| 29.3 | 136 | ||
| 29.5 | 96 | ||
| 30.0 | 114 | ||
| 29.9 | 146 | ||
| 29.8 | 227 | ||
| 28.4 | 214 | ||
| West Bengal | 26.9 | 248.3 |
In mid-June or early July, the monsoon season starts.[18] It continues until the end of September or early October.
In most places, the temperature drops as cloud cover increases. This is less true for the mountains and the Terai Dooars plains, where temperature gradually increases until August.
The maximum temperature of South Bengal's plains and western highlands is 32 °C,[19] 31 °C in North Bengal plains and around 19–20 °C in mountains. Sometimes when the sky gets clear, the temperature rises suddenly. This is known as a monsoon break. This occurs mostly in North Bengal plains and in mountains in July and August when the temperature soars over 36 °C and 24 °C respectively.[20] [21] [22] [23] [24]
Most of the annual rainfall occurs during the monsoon period. Heavy rainfall above 250 cm is observed in the Darjeeling, Jalpaiguri, Alipurduar and Cooch Behar district.[25] [26] [27] [28] [29] Later, blowing westwards, the winds cause average rainfall of 125 cm in the northern plains and western plateau region.
| City | Average temperature (°C) | Average Rainfall (mm) | |
|---|---|---|---|
| 16.4 | 2796 | ||
| 28.1 | 2651 | ||
| 28.0 | 2674 | ||
| 29.6 | 1207 | ||
| 29.4 | 1510 | ||
| 30.2 | 1036 | ||
| 29.4 | 1348 | ||
| 29.5 | 1140 | ||
| 30.3 | 1227 | ||
| 29.6 | 1358 | ||
| 29.1 | 1192 | ||
| West Bengal | 28.1 | 1649.0 |
Autumn lasts for two months, October and November.
In autumn, the southwest monsoon wind returns and clears the sky. So, the state gets enough sunshine to be warm in the day and releases a lot of heat to be cool at night.
At this time, a maximum temperature of 30–33 °C is felt over the plains and 17–19 °C in mountains. The minimum temperature is normally around 19–22 °C in plains and 6–11 °C in mountains.[30] Sometimes, cold waves blow over the state in autumn.[31] [32] [33]
In autumn, the southwest monsoon wind returns, and the northeast monsoon wind enters West Bengal. Due to their collision in Bay of Bengal, some cyclones are created.[34] [35] The cyclones cause some rainfall in the state.
| City | Average temperature (°C) | Average Rainfall (mm) | |
|---|---|---|---|
| 13.4 | 74 | ||
| 23.2 | 181 | ||
| 23.6 | 169 | ||
| 26.2 | 132 | ||
| 25.3 | 212 | ||
| 26.2 | 146 | ||
| 26.5 | 175 | ||
| 24.8 | 125 | ||
| 25.9 | 94 | ||
| 26.6 | 216 | ||
| 25.9 | 240 | ||
| West Bengal | 24.3 | 160.4 |
The winter season usually starts in December and ends in February.[36]
In winter, a mild temperature is observed over the plains. The maximum temperature goes to 23–26 °C and the minimum temperature is 9–15 °C in plains of the state. The maximum and minimum temperature in the mountains range from 0–12 °C. Higher regions of the Darjeeling Himalayas get heavy snowfall during winter.[37] [38] [39]
The temperatures of the western highlands at night can drop 7–9 °C,[40] [41] [42] 4–7 °C in Siliguri, Jalpaiguri, Coochbehar plains[43] [44] [45] [46] and 10–11 °C in Kolkata[47] [48] [49] [50] when cold waves blow. Darjeeling's temperature can drop below freezing point.
Winter is generally dry. Most days are sunny. Occasionally, slight rainfall occurs because of conditions in northwest India. These are known as western disturbances.
| City | Average temperature (°C) | Average Rainfall (mm) | |
|---|---|---|---|
| 7.6 | 30 | ||
| 17.3 | 60 | ||
| 18.9 | 36 | ||
| 20.6 | 27 | ||
| 19.7 | 44 | ||
| 20.6 | 32 | ||
| 20.5 | 29 | ||
| 19.7 | 46 | ||
| 20.1 | 42 | ||
| 21.6 | 35 | ||
| 21.1 | 43 | ||
| West Bengal | 17.0 | 38.5 |
Sources: India Meteorological Department[51] [52]
The chart below shows the highest recorded temperatures in individual stations, for all months in West Bengal, with place and date.
| Month | Highest Recorded Temperature (°C) | Place | Date | |
|---|---|---|---|---|
| January | 36.8 | 1 January 1977 | ||
| February | 39.3 | 26 February 2006 | ||
| March | 44.5 | 27 March 1980 | ||
| April | 47.2 | 30 April 2024 | ||
| May | 48.3 | 23 May 1981 | ||
| June | 47.8 | 10 June 1966 | ||
| July | 43.0 | 22 July 1994 | ||
| August | 43.0 | 3 August 1994 | ||
| September | 41.0 | 11 September 1977 | ||
| October | 40.5 | 1 October 1978 | ||
| November | 38.5 | 6 November 1976 | ||
| December | 36.5 | 30 December 1984 | ||
| West Bengal | 48.3 | Behrampore | 23 May 1981 |
The chart below shows the lowest recorded temperatures in individual stations, for all months in West Bengal, with place and date.
| Month | Lowest Recorded Temperature (°C) | Place | Date | |
|---|---|---|---|---|
| January | -7.2 | 30 January 1971 | ||
| February | -6.4 | 2 February 1971 | ||
| March | -4.8 | 1 March 1971 | ||
| April | 0.0 | 16 April 1971 | ||
| May | 1.4 | 1 May 1981 | ||
| June | 4.6 | 14 June 1991 | ||
| July | 3.9 | 26 July 1944 | ||
| August | 7.4 | 24 August 1971 | ||
| September | 5.9 | 10 September 1991 | ||
| October | 3.2 | 31 October 1972 | ||
| November | -4.4 | 26 November 1970 | ||
| December | -4.6 | 29 December 1970 | ||
| West Bengal | -7.2 | Darjeeling | 30 January 1971 |
The chart below shows the lowest recorded temperatures in individual stations in the plains, for all months in West Bengal, with place and date.
| Month | Lowest Recorded Temperature (°C) | Place | Date | |
|---|---|---|---|---|
| January | 0.9 | 2 January 1986 | ||
| February | 2.2 | 5 February 1914 | ||
| March | 6.2 | 4 March 1965 | ||
| April | 8.1 | 9 April 2014 | ||
| May | 11.5 | 10 May 1987 | ||
| June | 13.8 | 12 June 1961 | ||
| July | 12.0 | 16 July 1995 | ||
| August | 12.4 | Sandheads | 7 August 1972 | |
| September | 10.4 | Sandheads | 2 September 1976 | |
| October | 10.0 | Sandheads | 1995 | |
| November | 6.4 | 30 November 1971 | ||
| December | 2.4 | 26 December 1961 | ||
| West Bengal | 0.9 | Krishnanagar | 2 January 1986 |
The chart below shows the maximum recorded rainfall in individual stations (observatories) in the state, for all months, with place and date.
| Month | Highest Recorded 24 hrs Rainfall (mm) | Place | Date | |
|---|---|---|---|---|
| January | 134.6 | 10 January 1967 | ||
| February | 161.0 | 19 February 1989 | ||
| March | 243.2 | Sandheads | 04 March 1990 | |
| April | 210.0 | 3 April 1994 | ||
| May | 615.0 | Sandheads | 17 May 1995 | |
| June | 507.5 | Sandheads | 21 June 1981 | |
| July | 884.5 | Sagar Islands | 22 July 1991 | |
| August | 490.0 | Sandheads | 22 August 1991 | |
| September | 593.6 | Sandheads | 25 September 1986 | |
| October | 419.2 | 5 October 1968 | ||
| November | 322.0 | Sandheads | 10 November 1990 | |
| December | 251.3 | 11 December 1981 | ||
| West Bengal | 884.5 | Sagar Islands | 22 July 1991 |
Annual rainfall varies in different parts of the state. North Bengal receives the highest rainfall, 200 to 400 cm. In the coastal areas rainfall is about 200 cm, in the Ganga plain and in the central part of the state rainfall is about 150–200 cm, and in the western plateau region the amount of rainfall received is about 100 to 125 cm. Drought is a common phenomenon in the Bankura and Purulia districts. Rainfall that occurs in the summer months often brings about heavy storms called Kalbaishakhi.
| Name | Lowest Pressure (mbar) | Year | Winds (in km/h) | Image | |
|---|---|---|---|---|---|
| 966 | 1970 | ||||
| 964 | 1981 | ||||
| 994 | 1997 | ||||
| 984 | 1998 | ||||
| 998 | 2000 | ||||
| 970 | 2002 | 100 | |||
| 944 | 2007 | 215 | |||
| 996 | 2008 | 85 | |||
| 970 | 2009 | 120 | |||
| 986 | 2015 | 75 | |||
| 983 | 2016 | 85 | |||
| 978 | 2017 | 110 | |||
| 925 | 2020 | 240 |
Because of the high altitude, mountainous parts of Darjeeling and Jalpaiguri experience a cool temperate and climate. The average temperature in summer is about 15°C, and winter temperature is about 2°C. Snowfall occurs in some parts of this region. Being obstructed by the Himalayas, the region receives heavy rainfall. Due to the scenic beauty and temperate climate of the region, a huge number of tourists visit the areas. Here Kalimpong is another hill station that is visited by many tourists in all seasons for its scenic beauty and the average cool temperature throughout the year.