Generally, two defining factors that govern the best time to visit Nepal are weather and corresponding date of festival. The weather in Nepal or the Himalayas regions are generally quite unpredictable due to varied topographical features. In general sense the weather is probably the best guide for deciding when to plan your trip to Nepal. October and November are considered the best times of the year. The monsoon will have just ended, and clear skies with optimal temperature will prevail. The main festivals of Dashain and Tihar (Two big Hindu festivals) fall during these months. However, this is also the busiest tourist season, and the main tourist centers and trekking trails tend to be crowded with travelers like you. The tourist flow ebbs a little, but not significantly, between the winter months of December and mid-February. It catches up once again between mid-February and mid-April. From mid-June to early October, it’s the monsoon, during which time it rains almost every day and most of the Himalayas are hidden behind the clouds. In short, plan to visit Nepal between October and May, keeping in mind that October-November and February-March are the best times (but crowded with other travelers).