Hangzhou has a subtropical monsoon climate characterized by distinct four seasons, simultaneous rainfall and rain, and high humidity. The average annual temperature is 18.9°C, and annual precipitation exceeds 1,600 mm.
Seasonal Climate Characteristics:
Spring (March-May): Rainy and humid, with occasional "return of the south wind" ("return of the south wind"). Air humidity often exceeds 90%, but its duration is shorter than in South China (3-5 days).
Summer (June-August): Hot and humid, with an average temperature of 28°C in July and extreme highs reaching 43.3°C (recorded in 2024). "Sauna days" are frequent, with the highest temperature in the main urban area reaching 36.6°C in August 2025. Combined with humidity exceeding 70%, the temperature feels quite oppressive.
Autumn (September-November): Cool and dry, with a wide temperature difference between day and night. The average temperature in September is 21-25°C, making it suitable for outdoor activities.
Winter (December-February): Mild with little rainfall. The average temperature in January is 4-6°C, with an extreme low of -7°C (recorded in Lin'an in 2024). The air feels damp and cold.
Key Meteorological Data:
Temperature: The average annual temperature in the urban area in 2024 was 18.9°C, with an annual extreme temperature range of 50.3°C.
Precipitation: The average annual precipitation is approximately 1,600 mm, reaching 1,655.8 mm in 2024. Summer precipitation accounts for over 40% of the total precipitation. In July 2025, the main urban area received 381.6 mm of precipitation (133% above average).
Sunshine: Annual sunshine hours are 1,959, with a sunshine rate of 44%.