The Kathmandu Valley experiences a subtropical highland climate (Köppen classification Cwa), heavily influenced by the South Asian monsoon.
* **Temperatures:** Summers (June–August) are warm and humid, with average highs around 28°C (82°F). Winters (December–February) are mild and dry, with sunny days averaging 15°C (59°F) and chilly nights that can drop to 2°C (35°F). * **Precipitation:** The vast majority of the region's rainfall occurs during the monsoon season (June to September). Snowfall is exceedingly rare on the valley floor, though the surrounding hills occasionally receive a dusting. * **Best Time to Visit:** Autumn (September to November) and Spring (March to May) offer clear skies, comfortable temperatures, and ideal conditions for exploring the open-air monuments. * **Natural Disasters:** The region is highly vulnerable to seismic activity. Earthquakes are the primary natural threat to the preservation of the historical monuments.