Nepal is divided into three regions; Terai, Hill, and Mountains. The country has five seasons- winter, spring, summer, monsoon, and autumn. The weather and climate vary from one region to another as per the season.
Nepal has five seasons (winter, spring, summer, monsoon, and autumn), and weather/climate varies from one region to another as per the season.
December to February is the coldest time of the year. The season brings extreme cold all over the country, and due to fog, visibility gets poor. The mountain region sees heavy snowfall and snowstorms, which makes any kind of voyage dangerous in the Himalayas in winter. The temperature falls below -15°C in the mountains. Whereas, Kathmandu and Terai have temperatures ranging from 10°C to 0°C.
March to April is the best time of the year to trek in the Himalayas or climb high mountains. Professional trekkers and climbers love this season because of the bright day, constant weather, moderate climate, and hint of warmth in the air.
The mountains get covered in the snow, resulting in stunning panoramas. Thousands of wildflowers and vegetation cover all trekking trails in the lower Himalayas. The temperature ranges from 12°C to 0°C and below in the mountains.
May to July that covers the summer/monsoon period in Nepal is off-season for any trip in the Himalayas. You can travel in early May, and that's it. In the summer season, the climate begins to get hotter, and the chances of precipitation hikes too. The temperature ranges from 31°C to 0°C in the hilly and mountain region. Whereas, Terai region sees temperatures above 41°C.
The uncertain weather and heavy snowfall make the trail risky. The good news is there are two exquisite parts of Nepal, Upper Mustang and Dolpo, where you can trek even in summer and monsoon. These two parts of Nepal fall under the rain shadow of the Himalayas, therefore do not receive rainfall in the monsoon. Moreover, because of the restricted area not many people trek in this region which makes the trip surreal.
Autumn is the second-best traveling season in Nepal, especially in the Himalayas. The months are late-September to November. The climate usually is warm with a little hint of cold air and humidity. The lower part of Nepal is more on the tropical side. The temperature ranges from 18°C to 12°C in hills and mountains. Whereas, Terai sees a high temperature of 32°C to 25°C.
The stable weather and clear views make the trek in the Himalayas pleasant. Autumn is also the festival season in Nepal. If you are right on time, then you may get to participate in some of the biggest festivals celebrated by Nepalese all over the country.