Changshu is warmest in August, averaging 33° by day and 25° at night. The wettest month is July with 288 mm, and the year brings about 1437 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 10° | -0° | 56 mm | 6° | 10.1 h | Cool |
| February | 12° | 1° | 81 mm | 6° | 10.9 h | Cool |
| March | 17° | 5° | 112 mm | 10° | 11.8 h | Mild |
| April | 22° | 10° | 90 mm | 15° | 12.8 h | Sightseeing |
| May | 27° | 16° | 102 mm | 20° | 13.6 h | Beach weather |
| June | 31° | 21° | 228 mm | 24° | 14.1 h | Rainy season |
| July | 32° | 25° | 288 mm | 28° | 13.9 h | Rainy season |
| August | 33° | 25° | 146 mm | 30° | 13.2 h | Mild |
| September | 29° | 20° | 159 mm | 27° | 12.2 h | Mild |
| October | 24° | 14° | 81 mm | 22° | 11.2 h | Sightseeing |
| November | 19° | 8° | 72 mm | 16° | 10.4 h | Sightseeing |
| December | 10° | 1° | 22 mm | 9° | 9.9 h | Cool |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: May — highs around 27°, nights no colder than 16°, and at most 102 mm of rain in a month. The sea sits at 20–20° then.
Walking the city: April, October and November — highs of 19–24° and no more than 90 mm of rain a month.
Wet season: June and July — up to 288 mm in a single month.