March to June is the peak pleasant season. Temperatures are mild (10–25°C), the hills are green, and the lake is calm. This is when most domestic tourists come, and the town can be crowded at weekends. March and April are the quietest months of this window.
The monsoon arrives in mid-June and lasts until mid-October. Rain is heavy, landslides are a real risk on the approach roads, and mist frequently closes in. Some visitors find the dramatic weather atmospheric; others find the mud and restricted views frustrating. If you go in the monsoon, build in flexibility and check road conditions before driving.
October and November are excellent: post-monsoon clarity means the best Himalayan views, and the crowds have thinned. Temperatures drop from November onwards. December to February is cold, sometimes frosty, and occasionally sees light snowfall. The town is quiet and some hotels close.