Weather in Hangzhou

July is the warmest month (average 28.6°C, high 32.6°C) and January is the coolest (average 4.1°C, low -0.6°C). That 24.5°C swing in monthly averages is the first thing to plan around in Hangzhou.

Rain is wet season runs from February to September, inside an annual total of 1427 mm. The wettest month is June at 230 mm; the driest is December at 59 mm. Hangzhou is in China at 30.3°N. The 2001–2020 NASA POWER daily record describes a continental climate with a wide temperature swing. On this site the months that score closest to a 22°C day, lighter rain, and moderate humidity are May, September, and October.

When Hangzhou gets wet

The wet season in Hangzhou starts in February and ends in September (February, March, April, May, June, July, August, and September). June is the core of it at 230 mm. December is the other extreme, with 59 mm.

Humidity peaks near 82%. That usually lines up with the wetter months rather than the hottest ones.

Temperature through the year

Monthly average highs run from 8.7°C in January to 32.6°C in July. Nights follow the same curve: -0.6°C in January and 24.6°C in July.

Across the year the mean afternoon high is 21.8°C. If you want the smallest day–night shock, look at months where the high and low sit close together; July nights still hold 24.6°C.

What stands out month by month

The year bottoms out in January. Plan for -0.6°C at night and 8.7°C in the afternoon. February is when the wet season typically starts in Hangzhou: highs near 11.4°C, and rainfall jumps to 90 mm (12 rainy days). March: 16.1°C high, 4.9°C low, 106 mm rain, 79% humidity. April stands apart from the months beside it: 22.1°C / 10.4°C and 115 mm. May brings 124 mm and 13 rainy days; temperatures run from 16.0°C to 27.0°C. June is the wettest month — 230 mm and 17 rainy days, with 80% humidity.

Peak heat arrives in July: 32.6°C by day, 24.6°C at night, and 82% humidity. August stands apart from the months beside it: 32.4°C / 24.3°C and 177 mm. By September the wet season is ending. Hangzhou still sees about 129 mm, but the next month is usually leaner. October: 24.1°C high, 13.6°C low, 74 mm rain, 77% humidity. In November, Hangzhou averages 18.1°C by day and 7.5°C at night, with 77 mm of rain. December is the driest month, averaging only 59 mm across 8 rainy days. Highs sit near 11.0°C.

When the score favours a visit

The three months with the highest comfort score are May, September, and October: May (21.5°C average, 124 mm, 76% humidity); September (24.3°C average, 129 mm, 80% humidity); October (18.9°C average, 74 mm, 77% humidity). They fall in calendar order. The score rewards averages near 22°C, lower rainfall, and humidity near 60%. It is a climate score, not a festival or price calendar.

If you want the wet season itself — fewer crowds, greener landscape, heavier rain — aim at February–September instead of the score.

Hangzhou and other cities in China

Shanghai is about 161 km away: Hangzhou is about as warm as Shanghai at the hot peak and 141 mm wetter over the year than Shanghai. Shanghai’s wettest month is June (195 mm) versus June here.

Nanjing is about 237 km away: Hangzhou is about as warm as Nanjing at the hot peak and 230 mm wetter over the year than Nanjing. Nanjing’s wettest month is July (243 mm) versus June here.

Hefei is about 325 km away: Hangzhou is about as warm as Hefei at the hot peak and 273 mm wetter over the year than Hefei. Hefei’s wettest month is July (227 mm) versus June here.