Climate of Kolkata
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Kolkata has a Tropical savanna climate (Köppen climate classification Aw). The annual mean temperature is 26.8 °C (80.2 °F); monthly mean temperatures range from 15 to 30 °C (59 to 86 °F).[1] Summers are hot and humid with temperatures in the low 30's and during dry spells the maximum temperatures often exceed 40 °C (104 °F) during May and June.[1] Winter tends to last for only about two and a half months, with seasonal lows dipping to 9–11 °C (48–52 °F) between December and January. The highest recorded temperature is 43.9 °C (111.0 °F) and the lowest is 5 °C (41 °F).[1] Often during early summer (mid-March to mid-May), dusty squalls followed by spells of thunderstorm and heavy rains lash the city, bringing relief from the humid heat. These thunderstorms are convective in nature, and is locally known as Kal Baisakhi (কালবৈশাখী, Nor'westers).[2]
Rains brought by the Bay of Bengal branch of South-West monsoon[3] lash the city between June and September and supplies the city with most of its annual rainfall of 1,836.5 mm (72.30 in). The highest rainfall occurs during the monsoon in July and August interchangeably. The city receives 2578 hours of sunshine per annum, with the maximum sunlight occurring in March.[4] Pollution is a major concern in Kolkata, and the Suspended Particulate Matter (SPM) level is high when compared to other major cities of India,[5][6] leading to regular smog and haze. Severe air pollution in the city has caused a rise in pollution-related respiratory ailments such as lung cancer.[7]
| Climate data for Kolkata (Alipore) 1991–2020, extremes 1901–present | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 32.8 (91.0) |
38.4 (101.1) |
41.1 (106.0) |
43.3 (109.9) |
43.7 (110.7) |
43.9 (111.0) |
39.9 (103.8) |
38.4 (101.1) |
38.9 (102.0) |
39.0 (102.2) |
34.9 (94.8) |
32.5 (90.5) |
43.9 (111.0) |
| Mean maximum °C (°F) | 29.8 (85.6) |
33.9 (93.0) |
37.5 (99.5) |
38.8 (101.8) |
39.0 (102.2) |
37.8 (100.0) |
36.0 (96.8) |
35.3 (95.5) |
35.5 (95.9) |
35.3 (95.5) |
33.1 (91.6) |
30.0 (86.0) |
39.8 (103.6) |
| Mean daily maximum °C (°F) | 25.5 (77.9) |
29.4 (84.9) |
33.7 (92.7) |
35.4 (95.7) |
35.5 (95.9) |
34.1 (93.4) |
32.5 (90.5) |
32.3 (90.1) |
32.6 (90.7) |
32.3 (90.1) |
30.2 (86.4) |
26.7 (80.1) |
31.7 (89.1) |
| Daily mean °C (°F) | 19.9 (67.8) |
23.8 (74.8) |
28.2 (82.8) |
30.6 (87.1) |
31.2 (88.2) |
30.6 (87.1) |
29.5 (85.1) |
29.4 (84.9) |
29.4 (84.9) |
28.3 (82.9) |
25.1 (77.2) |
21.1 (70.0) |
27.3 (81.1) |
| Mean daily minimum °C (°F) | 14.3 (57.7) |
18.1 (64.6) |
22.9 (73.2) |
25.7 (78.3) |
26.8 (80.2) |
27.1 (80.8) |
26.7 (80.1) |
26.6 (79.9) |
26.3 (79.3) |
24.4 (75.9) |
20.1 (68.2) |
15.5 (59.9) |
22.9 (73.2) |
| Mean minimum °C (°F) | 10.9 (51.6) |
12.4 (54.3) |
18.2 (64.8) |
21.1 (70.0) |
21.8 (71.2) |
23.9 (75.0) |
24.3 (75.7) |
24.6 (76.3) |
23.9 (75.0) |
20.9 (69.6) |
16.9 (62.4) |
11.9 (53.4) |
10.0 (50.0) |
| Record low °C (°F) | 6.7 (44.1) |
7.2 (45.0) |
10.0 (50.0) |
16.1 (61.0) |
17.9 (64.2) |
20.4 (68.7) |
20.6 (69.1) |
22.6 (72.7) |
20.6 (69.1) |
17.2 (63.0) |
10.6 (51.1) |
7.2 (45.0) |
6.7 (44.1) |
| Average rainfall mm (inches) | 15.4 (0.61) |
24.6 (0.97) |
36.8 (1.45) |
55.0 (2.17) |
118.5 (4.67) |
276.7 (10.89) |
371.6 (14.63) |
372.1 (14.65) |
325.0 (12.80) |
179.6 (7.07) |
32.6 (1.28) |
5.6 (0.22) |
1,813.3 (71.39) |
| Average rainy days | 1.1 | 1.5 | 2.1 | 3.2 | 6.2 | 12.6 | 17.5 | 16.8 | 13.6 | 7.4 | 1.4 | 0.7 | 84.2 |
| Average relative humidity (%) (at 17:30 IST) | 62 | 55 | 51 | 61 | 68 | 77 | 82 | 83 | 82 | 76 | 68 | 65 | 69 |
| Mean monthly sunshine hours | 213.9 | 211.9 | 229.4 | 240.0 | 232.5 | 135.0 | 105.4 | 117.8 | 126.0 | 201.5 | 216.0 | 204.6 | 2,234 |
| Mean daily sunshine hours | 6.9 | 7.5 | 7.4 | 8.0 | 7.5 | 4.5 | 3.4 | 3.8 | 4.2 | 6.5 | 7.2 | 6.6 | 6.1 |
| Average ultraviolet index | 7 | 9 | 11 | 12 | 12 | 12 | 12 | 12 | 11 | 9 | 7 | 6 | 10 |
| Source 1: India Meteorological Department (sun 1971–2000)[8][9][10][11] Weather Atlas[12] | |||||||||||||
| Source 2: Tokyo Climate Center (mean temperatures 1991–2020)[13] [14] | |||||||||||||
| Climate data for Kolkata (Dumdum Airport) 1991–2020, extremes 1939–2012 | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °C (°F) | 32.5 (90.5) |
37.3 (99.1) |
40.6 (105.1) |
42.8 (109.0) |
43.1 (109.6) |
43.7 (110.7) |
39.2 (102.6) |
37.7 (99.9) |
37.5 (99.5) |
36.8 (98.2) |
36.0 (96.8) |
33.0 (91.4) |
43.7 (110.7) |
| Mean daily maximum °C (°F) | 25.3 (77.5) |
29.2 (84.6) |
33.6 (92.5) |
35.9 (96.6) |
36.1 (97.0) |
34.8 (94.6) |
33.2 (91.8) |
33.0 (91.4) |
33.3 (91.9) |
32.5 (90.5) |
30.1 (86.2) |
26.6 (79.9) |
32.0 (89.6) |
| Daily mean °C (°F) | 18.8 (65.8) |
22.9 (73.2) |
27.4 (81.3) |
30.1 (86.2) |
30.6 (87.1) |
30.3 (86.5) |
29.5 (85.1) |
29.3 (84.7) |
29.3 (84.7) |
27.9 (82.2) |
24.3 (75.7) |
20.1 (68.2) |
26.7 (80.1) |
| Mean daily minimum °C (°F) | 12.9 (55.2) |
16.9 (62.4) |
21.9 (71.4) |
25.2 (77.4) |
26.2 (79.2) |
26.8 (80.2) |
26.6 (79.9) |
26.5 (79.7) |
26.2 (79.2) |
24.1 (75.4) |
19.3 (66.7) |
14.3 (57.7) |
22.2 (72.0) |
| Record low °C (°F) | 5.0 (41.0) |
6.1 (43.0) |
12.1 (53.8) |
16.6 (61.9) |
17.6 (63.7) |
19.2 (66.6) |
20.1 (68.2) |
21.1 (70.0) |
21.7 (71.1) |
15.7 (60.3) |
11.7 (53.1) |
6.1 (43.0) |
5.0 (41.0) |
| Average rainfall mm (inches) | 15.8 (0.62) |
20.2 (0.80) |
31.9 (1.26) |
53.4 (2.10) |
140.5 (5.53) |
247.5 (9.74) |
366.5 (14.43) |
355.4 (13.99) |
282.1 (11.11) |
170.2 (6.70) |
21.3 (0.84) |
6.8 (0.27) |
1,711.5 (67.38) |
| Average rainy days | 1.1 | 1.4 | 2.3 | 3.5 | 6.6 | 12.4 | 17.6 | 17.1 | 13.0 | 7.1 | 1.1 | 0.7 | 83.8 |
| Average relative humidity (%) (at 08:30 IST) | 61 | 53 | 49 | 58 | 66 | 76 | 81 | 82 | 81 | 75 | 67 | 66 | 68 |
| Source 1: India Meteorological Department[14] | |||||||||||||
| Source 2: Tokyo Climate Center (mean temperatures 1991–2020)[15] | |||||||||||||
Weather Monitoring Stations
[edit]Alipore is the major station, which is an international station. But there are also two stations at Dum Dum and Salt Lake.
References
[edit]- ^ a b c "Weatherbase entry for Kolkata". Canty and Associates LLC. Retrieved 26 April 2006.
- ^ "kal Baisakhi". Glossary of Meteorology. American Meteorological Society. Archived from the original on 30 August 2006. Retrieved 5 September 2006.
- ^ Khichar, M.L.; Ram Niwas (14 July 2003). "Know your monsoon". Agriculture Tribune, The Tribune. The Tribune Trust. Retrieved 9 June 2007.
- ^ "Calcutta: Not 'The City of Joy'". Gaia: Environmental Information System. Archived from the original on 7 January 2019. Retrieved 26 April 2006.
- ^ Central Pollution Control Board. "Ambient Air Quality in Seven Major Cities During 2002". Ministry of Environment & Forests, Govt of India. Archived from the original on 25 February 2006. Retrieved 26 April 2006.
- ^ Central Pollution Control Board. "Air quality in major cities on 16–17 March 2006". Ministry of Environment & Forests, Govt of India. Retrieved 26 April 2006. [dead link]
- ^ Bhaumik, Subir (17 May 2007). "Oxygen supplies for India police". South Asia. BBC. Retrieved 23 June 2007.
- ^ "Station: Calcutta (Alipur) Climatological Table 1981–2010" (PDF). Climatological Normals 1981–2010. India Meteorological Department. January 2015. pp. 161–162. Archived from the original (PDF) on 5 February 2020. Retrieved 2 March 2020.
- ^ "Extremes of Temperature & Rainfall for Indian Stations (Up to 2012)" (PDF). India Meteorological Department. December 2016. p. M237. Archived from the original (PDF) on 5 February 2020. Retrieved 2 March 2020.
- ^ "Table 3 Monthly mean duration of Sun Shine (hours) at different locations in India" (PDF). Daily Normals of Global & Diffuse Radiation (1971–2000). India Meteorological Department. December 2016. p. M-3. Archived from the original (PDF) on 5 February 2020. Retrieved 2 March 2020.
- ^ "Kolkata (Alipore) (42807)". India Meteorological Department. Retrieved 10 September 2022.
- ^ "Climate and monthly weather forecast Kolkata, India". Weather Atlas. Retrieved 17 June 2022.
- ^ "Normals Data: Kolkata/Alipore - India Latitude: 22.53°N Longitude: 88.33°E Height: 6 (m)". Japan Meteorological Agency. Retrieved 2 March 2020.
- ^ a b "Climatological Tables 1991-2020" (PDF). India Meteorological Department. p. 21. Archived from the original (PDF) on 1 January 2023. Retrieved 1 January 2023.
- ^ "Normals Data: Kolkata/Dum Dum - India Latitude: 22.65°N Longitude: 88.45°E Height: 6 (m)". Japan Meteorological Agency. Retrieved 2 March 2020.