Kathmandu weather in September

September in Kathmandu is warm and wet, marking the tail end of the monsoon season. Expect daytime temperatures around 25.8°C (78°F) and cooler nights at 18.7°C (66°F). Rainfall is substantial with 432mm falling across roughly 28 days, so mornings and afternoons often bring heavy showers. Despite the rain, you'll still get around 8.7 hours of sunshine daily, usually in the early morning or late afternoon. The air is thick with humidity, and the valley's iconic views of the Himalayas remain obscured by monsoon clouds.

Culturally, September is a quieter time in Kathmandu. The monsoon keeps most tourists away, meaning lower prices and fewer crowds at temples like Pashupatinath and Boudhanath. The city feels fresher after the intense summer heat, and locals are preparing for Dashain, Nepal's biggest festival, which typically falls in October. The lush green landscape is at its most vibrant thanks to months of rainfall.

If you're considering visiting Kathmandu in September 2026, pack for wet weather and embrace the slower pace. Trekking is challenging due to rain and slippery trails, but city exploration, museum visits, and cultural experiences are rewarding. Book accommodation in advance despite lower tourism—many places still fill up during this shoulder season.