Our article published in Abiologic.
Nepal is situated between two giant countries: China in North and India in South. It consists of three regions: Himalayan, Hilly and Terai. The total area of the country is occupied by hilly and Himalayan regions. It covers about 86% of total land while remaining 14% with Terai Region. There is diversity in geographical condition of Nepal. All three regions have their own climatic and geographical conditions.
Himalayan region comprise Mountains and Ranges at high altitude, Hilly region has hills, valleys and grassland while Terai is a flatland. The Himalayas and the Hills within these boundaries makes Nepal famous worldwide for its mountainous and hilly topography. This as well results Nepal encountering almost all types of climates. The variation in temperature is because of change in topography mainly in the south and north direction. Wide range of climatic condition seen in Nepal due to rapid change in altitude. Generally, in western part of world there are four season’s altogethers, but two additional seasons in Nepal. Seasons in Nepal last for two months.
Seasons of Nepal are: Spring (Basanta Ritu), Summer (Grishma Ritu), Rainy (Barsha Ritu), Autumn(Sharad Ritu), Pre-Winter(Hemanta Ritu), Winter(Shishir Ritu). The addtional two are: Rainy Seasons and Pre-Winter Season from the list. Spring season in Nepal starts from mid-March and end in mid-May. The temperature of this season is just too favourable. It is neither too hot nor too cold. Summer starts from mid-May and ends in mid-July. These are the best time for cultivation and are the hottest season among other. Rainy season begins from mid-July and ends in mid-September. Excessive rainfall happens during this season which aids in irrigation to agricultural crop. Sharad Ritu starts from mid-September and ends in mid-November. This is also known and festival season. The biggest festival of Nepal: Dashain, Tihar and Teej fall in this season. Hemanta Ritu begins from mid-November and ends in mid-January. People harvest their crops during this part of season. Temperate is mild and starts to fall in this season inviting winter. Shishir Ritu begins from mid-January and ends in mid-March. Snow Falls in this season and is the coldest season of the year. Summer is the monsoon season in Nepal and is the favorable and the best time for travelers and trekkers. Bay of Bengal governs the climatic condition specially monsoon in Nepal. The hills turn lush and green and people actually the natural beauty seekers wants to spend relaxed time with nature.
There are various factors that affect the weather and temperature. Some of them are Climate, Particle Size, Exposure, Minimal Composition, Topography and Time. Physiography, the monsoonal winds and the aspect of mountain slope are also the major causes for extreme variation of weather in Nepal. Rainfall in Nepal whose major source is Monsoon and in June to September approximately 80% of annual rainfall occurs. But, sometimes no doubt the expected time for rainfall diminished because of season irregularity. This untimely excessive rainfall results floods and landslides. Considering another leading factor for diverse weather is altitude. River beds are wet while high elevations and temperature at higher altitude is freezing cold. In Terai is hot excessively during peak summer season. Thus, temperature in three regions varies accordingly. Variation in temperature observed while traveling from south towards North as hot, warm, cool, cold, and very cold. Extreme maximum temperature observed more than 45oC in Terai Region while extreme minimum temperature Observed less than -20oC in mountain region. Hilly region is in between 25-30oC. Different statistics and the readings have found the topography and monsoon are of major influence on the temperature variation in Nepal. Maximum temperature recorded is in the trend of increasing yearly than the minimum temperature in almost all the seasons. The analysis shows that mean annual maximum temperature over Nepal is 0.04oC/year whereas minimum temperature are only 0.01oC/year.