GENERAL

CLIMATE

[The write-up on Climate is contributed by the Meteorological Department, Government of India, Pune.]

The climate of the district is characterised by a hot summer and general dryness during major part of the year except during south-west monsoon season. The cold season in the district commences from December and ends in the month of February. The period from March to the first week of June is the hot season. It is followed by the southwest monsoon season which lasts till the end of September; October and November constitute the post-monsoon or the retreating south-west monsoon season.

Rainfall : Records of rainfall in the district are available for 13 rain-gauge stations for periods extending from 47 to 83 years. Tables 2 and 3 given below give the details of the rainfall at these stations and for the district as a whole. The average annual rainfall in the district is 578.8 mm. (22.79"). The district mostly is in rain shadow to the east of western ghats. Near the western border of the district the rainfall decreases rapidly as one proceeds towards east. But from a line roughly north-south in the central parts of the district the rainfall gradually increases towards the east. About 77 per cent of the annual rainfall in the district is received during the south-west monsoon season, September being the rainiest month. The variation in rainfall from year to year is large. The highest annual rainfall amounting to 159 per cent of the normal occurred in 1916, while 1920 was the year with the lowest annual rainfall which was 51 per cent of normal. In the fifty year period from 1901 to 1950 the annual rainfall in the district was less than 80 per cent of the normal in 15 years with three consecutive years of such rainfall occurring once and two consecutive years thrice. Considering the annual rainfall at the individual stations two and three consecutive years of rainfall less than 80 per cent of the normal is common at many stations. Even four consecutive years of such low rainfall occurred once each at four of the stations. It will be seen from Table No. 2 that the annual rainfall in the district was between 300 and 800 mm. (11.81" and 31.50") in 44 years in the fifty year period.

On an average there are 35 rainy days (i.e., days with rainfall of 2.5 mm. -10 cents - or more) in a year in the district. This number varies from 31 at Rahuri and Sangamner to 41 at Akola.

The heaviest rainfall in 24 hours recorded at any station in the district was 330.2 mm. (13.00") at Kopargaon on 15th October 1951.

Temperature : There is a mateorological observatory in the district at Ahmadnagar functioning from 1891. The records of this observatory may be taken as representative of the meteorological conditions prevailing over the district. The cold weather starts by about the middle of November and continues till the end of February. December is the coldest month of the year with the mean daily maximum temperature at 28.5° C (83.3° F) and the mean daily minimum at 11.7° C (53.1° F). During the cold season the district is sometimes affected by cold waves in association with the passage of western disturbances across north India, causing drop of minimum temperature to 2° to 3° C (35.6° to 37.4° F). From March to the break of south-west monsoon the day temperatures increase progressively, the nights remaining comparatively cool. In the hot season, the sweltering heat of the afternoons is sometimes relieved by thunder-storms. May is the hottest month of the year with the mean daily maximum temperature at 38.9° C (102.0° F) and the mean daily minimum at 22.4° C (72.3° F). On individual days during the hot weather period temperature occasionally goes up to 43° or 44° C (109.4° or 111.2° F). With the onset of southwest monsoon in the district there is an appreciable drop in temperature and weather becomes pleasant. With the withdrawal of the monsoon by about the first week of October day temperatures increase slightly and a secondary maximum in day temperatures is recorded in October. However the night temperatures decrease steadily after the withdrawal of the monsoon.

The highest maximum temperature recorded at Ahmadnagar was 43.7° C (110.7° F) on 9th May 1960 and the lowest minimum 2.2° C (36.0° F) on 7th January 1945.

Humidity : The air is generally dry during the months from February to May and particularly so in the afternoons when the humidity is about 20 per cent on the average. The relative humidities during south-west monsoon period are between 60 and 80 per cent. Thereafter they decrease rapidly.

Cloudiness : Skies are generally heavily clouded to overcast during monsoon months. In the post-monsoon months the cloudiness decreases. In the rest of the year the skies are clear or lightly clouded.

Winds: Winds are generally light to moderate with some strengthening in the south-west monsoon season. In the south-west monsoon season winds are from directions between south-west and north-west. In the post-monsoon season winds from the north-west and north are common in the mornings while in the afternoons the winds blow from directions between north and east. In the cold season winds are variable in directions, winds between north-west and south-west being more common. In the summer season northerly to north-westerly winds are more common, but by May westerlies also begin to blow in the afternoons.

Special weather phenomena : Thunder-storms occur during the months from March to June and in September and October. Dust-storms are very rare in the district. The district experiences cloudy to overcast skies with wide-spread heavy rain in association with the monsoon depressions that form in Bay of Bengal and move across central parts of the country.

Tables Nos. 2, 3, 4, 5 and 6 give the frequency, normals and extremes of rainfall, temperature and humidity, mean wind-speed and special weather phenomena respectively for Ahmadnagar:

TABLE No. 2-FREQUENCY OF ANNUAL RAINFALL IN THE

DISTRICT (DATA: 1901-1950)

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