The months of October and November are peak trekking season in Nepal: temperatures are mild, the weather is relatively stable, and the clear air makes for superb mountain views. The high mountains are still cold and and lower elevations are still warm but the daytime walking temperatures are the most pleasant overall. Bad weather can hit any time of year but the fall has the most reliable conditions.

 The second most popular time of the year for trekking in Nepal is from late February through April. The spring temperatures are similar to the fall and the trails are less crowded, but there is slightly more haze and precipitation. This means that in the spring you will need to reach higher elevations for clear mountain views, usually around 10,000 feet and above. Precipitation levels increase as the spring progresses.

 The shoulder seasons can be excellent, particularly the second half of September and early December, but they are also more good views during a trip. If you’re lucky, you will experience peak season conditions with only a fraction of the trekkers. If the monsoon lingers or the winter arrives early, the weather won’t be nearly as pleasant.

 The summer from May through August generally is a less time to trek in Nepal (lower elevation hill treks and the drier Mustang and Dolpo regions can be exceptions to the rule). Significant heat and moisture rise up from the Indian Ocean, bringing hot temperatures, clouds, haze, and rain. This blocks the views, creates messy trails (with leeches), and leads to significant problems with ground transportation. The peak of the Monsoon season occurs in July when the weather begins to taper off into the drier fall period.