GENERAL

CLIMATE

[This section on ' Climate ' was contributed by the Meteorological Department of the Government of India, Poona.]

Seasons.

The climate of this district is on the whole agreeable. The year may be divided broadly into four seasons. The cold season is from December to about the middle of February. The hot season, which follows lasts till the end of May. June to September is the southwest monsoon season and the two months October and November form the post-monsoon or the retreating monsoon season.

Rainfall.

The district has a good network of 15 rainguage stations for most of which records are available for more than 80 years. The details of the rainfall at these stations and for the district excluding the hilly portions along the western border are given in the tables No. 2 and 3. The rainfall in the belt roughly 15 to 20 miles wide, parallel to the crests of the Sahyadrian Range, is considerably higher than in the rest of the district. While Mahableshwar at an elevation of 1,372 metres (4,500 ft.) gets an average annual rainfall of 6,226 mm. (245.13") other stations in this belt get annual rainfall ranging between 1,723 and 1865 mm. (67.85" and 73.43"). The rainfall generally decreases first rapidly and then gradually from the Western Ghats towards the eastern boundary of the district. Some rainfall in the form of thundershowers occurs in May, but the main rainy season is from June to September. The rainfall in the south-west monsoon months is about 71 per cent, of the annual total. July is the month with the heaviest rainfall. About 18 per cent, of the annual rainfall is received in the post-monsoon months of October and November. The annual rainfall at individual stations shows considerable variations from year to year. It will be seen from table No. 2 that at some stations the rainfall has been as much as double the normal in some years while in some others rainfall has been less than half the normal. Considering the district as a whole excluding the narrow strip along the western border which generally gets heavier rainfall, the variations in the annual rainfall have been large. In the fifty-year period from 1901 to 1950, the annual rainfall was the highest in 1932 and amounted to 150 per cent, of the normal. The year 1918 with the annual rainfall of 52 per cent, of the normal was the year with the lowest rainfall. In the same fifty-year period the annual rainfall was less than 80 per cent, of the normal in ten years. There were three occasions when two or three consecutive years had low rainfall. It will be seen from table No. 3 that in 34 years out of fifty, the rainfall in the district excluding the strip along the western boundary was between 500 and 800 mm. (19.69" and 31.50")

On an average there are 43 rainy days (i.e. days with rainfall of 2.5 mm.—.10 cents or more) in the district excluding the western hilly region. As in the case of the amount of rainfall, the number of rainy days are highest in the Ghat region and least in the eastern border region. While Mahabaleshwar on the western ghats has on an average 119 rainy days in a year, Mhaswad near the eastern border has only 30 rainy days in a year.

At Mahabaleshwar the highest rainfall in 24 hours ever recorded was 458.5 mm. (18.05") on June 3, 1882 and July 30, 1896. In the plains of the district, the highest rainfall in 24 hours at any station was 206.5 mm. (8.13") at Mhaswad on September 17, 1902.

Temperature.

The only meteorological observatory in the district is at Mahabaleshwar, for which meteorological records are available for a number of years. The meteorological conditions at this station represent only those on the Western Ghats. However, some meteorological data are available for Panchgani and Satara for about five years. The data for the latter station may well be taken as representative of the conditions over the plains of the district. The cold weather starts by about the end of November and continues to about the middle of February, December being the coldest month. In this season the mean daily maximum temperature in the plains is 28.4°C (83.1°F) while the mean daily minimum temperature is 14.4°C (57.9°F). At Mahabaleshwar the mean daily maximum temperature in December is only 23.1°C (73.6°F) and the mean daily minimum is 13.8°C (56.9°F). The period from the middle of February to the end of May is one of continuous increase in temperatures. The rise in temperatures is more marked in the plains than on the hills. In May, the hottest month in the year, the mean daily maximum temperature in the plains is 36.8"C (98.3°F). The heat is sometimes relieved by afternoon thunder showers. The onset of the south-west monsoon in the first or second week of June brings down the day temperatures appreciably. The day temperatures in the south-west monsoon months are even lower than in the cold season. After the withdrawal of the south-west monsoon, day temperatures show an increase in October. Thereafter, both day and night temperatures begin to drop. Except during the south-west monsoon season the daily range of temperature is large and is about 8 to 11°C at Mahabaleshwar and 12 to 15°C at Satara.

At Mahabaleshwar the highest maximum temperature ever recorded was 36.1° C (97.0° F) on April 3, 1934 and the lowest minimum was 3.9° C (39.0° F) on February 1, 1942. As the data for the station in the plains (Satara) is available only for a short period extreme values of the temperature have not been given.

Humidity.

In the south-west monsoon months the air is highly humid but in the summer and the cold seasons the air is dry particularly in the afternoons. In the plains, the dryness is more marked than in the hills.

Cloudiness.

During the south-west monsoon season skies are heavily clouded to overcast being markedly so on the hills. After the withdrawal of the monsoon cloudiness rapidly decreases and skies are clear or lightly clouded in the winter and the summer months. Clear skies are most common in March and April.

Winds.

Winds are strong particularly on the hills in the south-west monsoon season. In the rest of the year they are light to moderate. South-westerly or westerly winds prevail in the south-west monsoon months. In the post monsoon months, they are predominently north-easterly or easterly, but in the afternoons northerly winds blow on some days. During the cold season, winds are from directions between north-east and south-east in the mornings and between south-west and north-west in the afternoons. Northerly or northeasterly winds are common in the mornings during the hot season, while in the afternoons winds are mainly north-westerly and sometimes westerly.

Special Weather Phenomena.

Thunderstorms occur in the hot season and in the post-monsoon months. The rainfall in the south-west monsoon months is also sometimes accompanied with thunder. The hills are generally covered with clouds during the south-west monsoon season. Fogs occur occasionally in the valleys in the cold season.

Tables No. 4, 5 and 6 give the temperature and humidity, mean wind speed and frequency of weather phenomena, respectively, for Mahabaleshwar. The temperature and humidity data of Panchgani and Satara are given in tables 4 (a) and 4 (b), respectively, while the mean wind speeds at the two sations are given in tables 5 (a) and 5 (b).

No earthquakes and tremors were recorded in Satara district during the last 75 years.

TABLE No. 2.

NORMALS AND EXTREMES OF RAINFALL IN SATARA DISTRICT, DURING 1901-1950.

(a) Normal rainfall in mm. (b) Average number of rainy days (days with rain of 2.5 mm. or more).

TABLE No. 2. contd.

TABLE No. 2—contd.

(a) Normal rainfall in mm.

(b) Average number of rainy days (days with rain of 2.5 mm. or more).

* These stations are in the hilly portions of the district.

TABLE No. 2.contd.

(a) Normal rainfall in mm. (b) Average of rainy days (days with rain of 2.5 mm. or more).

*Based on all available data upto 1957.

**Years given in brackets.

TABLE No. 2. contd.

(a) Normal rainfall.

(b) Average number of rainy days (days with rain of 2.5 mm. or more).

*Based on all available data upto 1957.

**Years given in brackets.

Table No. 2. contd.

(a) Normal rainfall.

(b) Average number of rainy days (days with rain of 2.5 mm. or more).

*Based on all available data upto 1957.

**Years given in brackets.

TABLE No. 2. contd.

(a) Normal rainfall.

(b) Average number of rainy days (days with rain of 2.5 mm. or more).

*Based on all available data upto 1957.

**Years given in brackets.

TABLE No.3

FREQUENCY OF ANNUAL RAINFALL IN THE SATARA DISTRICT.

(EXCLUDING THE HILLY REGIONS).

(DATA 1901-1950).

TABLE No. 4.

NORMALS OF TEMPERATURE AND RELATIVE HUMIDITY IN SATARA DISTRICT.

(MAHABALESHWAR).

* Hours I.S.T.

TABLE No. 4. contd.

* Hours I.S.T.

TABLE No. 5.

MEAN WIND SPEED IN KILOMETRES PER HOUR.

(MAHABALESHWAR).

TABLE No. 6

SPECIAL WEATHER PHENOMENA, SHOWING MEAN NUMBER OF DAYS. (MAHABALESHWAR).

TABLE No. 4(a).

NORMALS OF TEMPERATURE AND HUMIDITY.

(PANCHGANI).

TABLE No. 5(a).

 MEAN WIND SPEED IN KILOMETERS PER HOUR. (PANCHGANI).

TABLE NO. 4 (b)

 NORMALS OF TEMPERATURE AND HUMIDITY.

(SATARA).

* Hours I. S. T.

TABLE No. 5 (b).

MEAN WIND SPEED IN KILOMETRES PER HOUR.

(SATARA)

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