Climate of Mizoram

Climate of Mizoram

Despite it tropical location Mizoram enjoys a moderate climate. This mainly due to its fairly high elevation. It is neither very hot nor too cold throughout the year. The region falls under the direct influence of the south-west monsoon. As such the region receives an adequate amount of rainfall. The climate is humid tropical, characterised by short winter, long summer with heavy rainfall.

Temperature : Since there are no proper observatory stations in Mizoram, it is not possible to give a comprehensive information about the temperature conditions of the region. The analysis is based mainly on the observations and data generated by the author with meagre temperature records available on the region.

The salient thermo-characteristics of Mizoram is that temperature do not fluctuate much throughout the year, excepting in the low-lying valley sites. However, it is observed that there has been a steady increase in the annual temperature, at par with the global phenomenon. The hottest months are May, June and July. Thereafter, the onset of monsoon brings down the temperature. The temperature continues to fall with the break of the monsoon rains, and it minimised in December and January. In autumn, the temperature is usually between 18ᵒC to 25ᵒC, while winter temperature records normally between 11ᵒC to 23ᵒC. The  summer temperature is usually between 25ᵒC to 34ᵒC. During the last 20 years or so, steady increase in temperature has been noticeable as felt in the global context, mainly due to the large-scale degradation of vegetation and mismanagement of environment.

During winter, the lowest temperature is felt at places having high altitudes such as Champhai, Zote, Ngur etc. In the east; Bualpui(Ng) and Phawngpui mountainous area in the south. The maximum temperature in summer is observed at relatively lower places such as Kanhmun, Zawlnuam, Bairabi, Vairengte etc. In the northern part; Tlabung, Chawngte, Tuipang, Tuipuibari etc. In the south and west-end. It is truly observed that places at higher altitude experience lower diurnal range of temperature; while places at lower altitudes have higher temperature ranges.

Rainfall : The entire state of Mizoram is under the direct influence of monsoon. It rains heavily from May to September. The average rainfall is 257 cms per annum. The north western portion of the state receives highest rainfall i.e. more than 350 cms. Per annum. The rainfall also increases southward with increase in humidity. While Aizawl located at 23ᵒ44’N and 92ᵒ43’E receives about 208 cms. Annual rainfall, Lunglei (22ᵒ53’N and 92ᵒ45’E) records as high as 350 cms. The study of the available rainfall data reveals that the highest monthly rainfall data in Mizoram was recorded in July 1983 which was 602.60 cms.

Precipitation is heavy in summer, normally from May to September, and lasts till late October. Normally July and August are the rainiest months, while December and January are the driest months.

Season: Depending on the variation in temperature and general weather conditions, there different types of seasons are observed in Mizoram. They are – (1) The cold season or winter, (2) Warm season or spring, and (3) Rainy season or Summer.

The Cold or Winter Season

The season starts from November and lasts till February. The temperature is comparatively lower (11ᵒC – 23ᵒC), but not too low to make human habitation difficult. The diurnal temperature varies from 8ᵒC to 24ᵒC during this season. The season receives very less rainfall and whatever amount rainfall received is originated from north east, generally known as retreating monsoon. The season is very pleasant with clear blue sky in the absence of cloud covering. Morning mists are common upon the valleys during the season; which give an enchanting view resembling a wide stretches of ice-sheets.

The Warm Season or Spring

The warm season begins from March and lasts till first part of May; and merges with rainy season. The temperature has risen upto a range of 19ᵒC to 29ᵒC being aggravated by rainless days. The early part of this season is characterized by bring sunshine and clear sky with little or no cloud till it is disrupted by the coming of pre-monsoon showers. Maximum diurnal temperature sometimes reaches as high as 32ᵒ centigrade. Due to little or no cloud covering, maximum insolation is received during this period; and this is the hottest season in Mizoram.

The Rainy Season or Summer

This is the longest season in Mizoram, hold out for nearly six months from second part of May till late October. The season starts with violent storms which swept the state from south west through Bay of Bengal, marking the beginning of monsoon rains. Rainfall is heavy during May to September, and about 40 per cent of the annual rainfall is received during July and August. The heavy outpours which start normally in the morning are sometimes associated with hailstorms and thunder. This is the season when cyclonic rains are often felt. The temperature remains high, but it kept down to a considerable extent by the usual rains.