Weather in Shanghai in September

A good month. September is a solid month to be in Shanghai. Highs average 28.2 °C, lows 21.5 °C, and rain falls on 12 days — nothing in the month is working against you.

September ranks 5 of 12 in Shanghai: past the worst of the year but short of October, which is the month to book if the dates are open.

Rain on 12 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 28.2 °C days and 21.5 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 7 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 36.6 °C and the coldest night fell to 13.6 °C, and the wettest single day dropped 89 mm — roughly 65% of the month's rain in one day.

September is moderately variable: 39 mm in the driest year against 291 mm in the wettest, around an average of 136 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 13.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.6 °C cooler than August, with October dropping another 4.8 °C. The first week and the last are not the same trip. Rain is the thing that moves: October brings 5 days less of it, so pushing the dates later buys drier weather.

Daylight in September

12.4 hours of daylight, losing 0.9 hours across the month. That is between Shanghai's extremes of 14.2 and 10.1 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 25.6 °C in September — warm enough to stay in as long as you like. This is the warmest the water gets all year.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

September in Shanghai versus nearby

If Shanghai is one option among several, the nearby comparison is worth making. Hangzhou is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Nanjing is close enough to be a coin toss — within a degree on temperature, 3 days less rain.

So: September works, with October the better month by 16 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Shanghai

See all twelve months in Shanghai, or where else to go in September.