CLIMATE
The sum total of weather over a period constitutes the climate. It is the net
result of various factors, the most important of which are temperature,
precipitation, wind, sunshine and clouds. Climate has a profound effect on the
economic development of a region. It has also a great bearing on the social and
cultural activities of the people.
SEASONS
There are three well defined seasons in the Punjab. These
are:
1. Hot Season (mid-April to the end of June)
2. Rainy Season ( early July to the end of September)
3. Cold Season (early December to the end of February)
The transitional seasons
are:
1. Post-monsoon (September to end of November). It is transitional period
between the rainy and cold seasons.
2. Pre-hot season (March to mid-April). It is a transitional period
between the cold and hot seasons.
Hot
Season
The temperature begins to rise from February onwards. Though the real hot
seasons starts in mid-April, the rising temperature breaks the high pressure
belt in the north-west of the Indian peninsula. The atmospheric pressure over
this region in February is about 987 milli bars. The minimum is reached in early
June when it is near about 970 milli bars.
Rainy
Season
This is the most welcome season and the agricultural year starts with its
advent. Monsoon winds reach the region normally in the first weeks of July. The
Bay of Bengal branch of the monsoon current is the main source of rainfall.
Winter
Season
The fall in temperature is minimum in January, when the mean temperature
falls to 12oC during day time and to 5oC during the night. The winter season,
cherished by the affluent, becomes a curse for the poor who cannot afford warm
clothing
Post-Monsoon
Transitional Season
Monsoon normally retreat by the middle of September. With this a gradual
change in weather takes place and continuous so till the end of November. Thus
October and November are the months with transitional climates between rainy and
winter seasons. The weather remains generally dry and fair.
Post-Winter
Transitional Season
By early March the winter season begins to fade and by the middle of April,
it ultimately emerges as hot season. At times there may be a shower or two
accompanied by hail storms and squalls which do a lot of damage to crops.
The winds are warm and dry during the last days of
March, it is the time for
harvest.
TEMPERATURE
The sub-tropical latitudinal and continental location of Punjab makes the
variation of temperature from month to month very high. Though the minimum air
temperature rarely drops below 0o C, ground frost is a common
phenomenon in mid -winter. The rise in temperature is gradual when the air has
high moisture content with the sky remaining overcast; the rise is however steep
when the sky is clear and there is little moisture content in the air.
The highest day time temperature is recorded during the months of May and
June. It is 40.4o C at Patiala, 40.4o C at Amristar and 41.2o C at
Ludhiana.
At Ludhiana the highest maximum temperature on record was 46.1o C
while at Amritsar and Patiala the highest record was 45.5o C. The
daily maximum temperature at Ludhiana remains above 41o C for 45 days
in a year. The lowest maximum temperature is recorded during the month of January . When
the sun's rays are more oblique as compared to the other months. The cold winds
check the rise of day temperature.
The minimum temperature is lowest from December to February. The lowest
minimum temperature recorded at Amristar is 0.2o C and at Ludhiana 0.5oC.
At Amristar the minimum temperature remain below 5oC for 55 days. The
maximum number of days with the lowest night time temperature are in the month
of January. The highest minimum temperature is recorded in the month of June. When it is
even higher than the day temperature of December and January. At Ludhiana
for 55 days in the year the minimum temperature is as high as 27o C.
The maximum number of days with such high night temperature are in the
month of June. The annual range of temperature all over the state is around 21oC.
The mean monthly range of temperature varies from 9oC in July
to about 18oC in November.
RAINFALL
The amount of rainfall in the Punjab ranges between 250 mm and 1000 mm. The
maximum falling near the Shivalik Hills and the minimum towards the desert
in the west. 70 to 80 percent of the total rainfall is concentrated during
the three months of south-west monsoon winds and the rest comes during the
winter months. There is wide difference in the amount of rainfall experienced in
east and west Punjab. Near the hills rainfall is over 1000 mm. Gurdaspur,
Hoshiarpur, Ropar district and eastern parts of Patiala receive an annual
rainfall of more than 750 mm. The 500 mm rainfall line runs in a north-west to
south-east direction and cuts the Punjab into almost two equal zones. The Fazilka tehsil
in the extreme west receive a rainfall of less than 250 mm.
Monsoon
Rainfall
The major part of annual rainfall is experienced during the monsoon period, when the monsoon current in the Bay of Bengal enters from the south-east. The
normal onset of the monsoon in Punjab is in the first week of July.
Winter
Rainfall
During the winter season, weather in Punjab is normally cool and dry. This type of
weather is associated with the passage of western disturbances through the
region.
The importance of winter rainfall in Punjab is immense primarily because of
its time and effectiveness. In the area adjoining the Shivalik Hills, winter
crops is dependent upon this rainfall. The sub-Shivalik region receives more than
100 mm of rainfall from December to March.
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