The best trekking season in Nepal extends from mid-September to May. However, within this period, some months have better weather than others. From early September the monsoon rains decrease. By mid-October through to December, the weather is usually stable with mild to warm days, cold nights, and clear views. Daytime temperatures can reach 25-30 deg C at low altitudes in October and nights can drop to below 0 deg C at higher altitudes.
Trekking in Nepal during the winter, from December to February, offers cool to mild weather with clear days and often very cold nights. Daytime temperatures at low altitudes will be mild, around 20 deg C, and at night may drop to 0 and can go as low as -10 deg C at the higher points. Occasionally winter storms can bring snow as low as 2500m.
In March the cold, dry winter season begins to give way to warmer, spring conditions. Mornings are usually clear with cloud build-up occasionally bringing afternoon rain. Daytime temperatures increase quickly in March, with temperatures of up to 30 deg C and mild nights at low altitudes. The increase in rainfall in the hills is more than compensated for by the spectacular displays of rhododendrons and other wildflowers at this time of year.
Late spring conditions, in May, are generally hot at low elevations, and as the clouds build up to the next monsoon, which generally begins in June, daily afternoon rainstorms are common. This is a period that generally has clear weather at higher altitudes and is traditionally a time when the big mountaineering expeditions commence their ascents.
The monsoon creates a rainy season in Nepal, which lasts from mid-June to mid-September. During this time, the Nepali Himalayas is unsuitable for trekking, with the exception of a few remote valleys. Nepal Spirit Adventure offers treks during this period in Tibet & Mt. Kailash as well as the Indian Himalayan regions of Kulu, Garhwal & Ladak places that are at their best during this time.
Lower Altitude Treks in Nepal: The weather patterns are not so predictable that you can be absolutely positive about weather conditions in advance, but there are well-established patterns. The lower altitude treks allow you to experience the forests, village culture, and fantastic mountain views, and extremes of weather are unlikely. Usually, weather conditions are mild throughout the trekking season.
Moderate Altitude Treks in Nepal: Like lower altitude treks the weather patterns are not so predictable that you can always be absolutely positive of weather conditions in advance, but once again there are well-established patterns. Moderate altitude treks will experience mostly mild weather conditions, however, the high camps can be subject to snowfalls and harsh weather, particularly in winter.
Mountaineering Treks in Nepal: We at Nepal Spirit Adventure operate our climbing/alpine expeditions during what is known as the pre and post-monsoon periods. At this time the weather, snow conditions, and temperatures are generally considered to be at their most stable, and this gives us optimum conditions for conducting a safe and successful expedition.
The post-monsoon period: From early September the monsoon rain starts to decrease. By mid-October through to mid-December, the weather is usually stable, with mild to warm days, cold nights, and clear views. Daytime temperatures can reach 25 - 30 degrees Celsius at lower altitudes and decrease as you gain height.
Over 3000 meters the daytime temperatures can vary as much as 10 to 20 degrees Celsius and may be hotter or colder, depending on whether it is sunny or windy, etc. At night at lower altitudes, temperatures do not normally drop much, although as you approach November it does get colder and the days shorter. Up high it can drop sharply at night, from 0 to minus 10 or 15, and more when camped on the ice or snow.
The pre-monsoon period: In March the cold, dry winter season begins to give way to warmer, wetter spring conditions. Mornings are usually clear with cloud build-up bringing occasional afternoon rainstorms. Views of the mountains in the middle of the day and afternoon may often be obscured.
Daytime temperatures increase quickly in March with temperatures of up to 30 degrees Celsius and mild nights. At higher altitudes it is similar to the conditions of the post-monsoon period; however, there is usually more snow, which has accumulated over the winter period.
There are spectacular displays of rhododendrons and wildflowers at this time of year. Late spring conditions, in April and May, are generally hot at low elevations and as the clouds build up to the next monsoon, daily afternoon rainstorms are common.