Chongqing Weather in September

Season: Transitional Period from Summer to Autumn
Overview:
1. Chongqing’s weather in September is turning slightly cooler, but you will still experience many hot days.
2. Rainfall is high. However, except for mountain areas, most other areas mostly see brief showers and nighttime rain this month, which will not be very unfavorable for traveling around.
3. September can be considered as one of the best times to visit Chongqing, as temperatures cool a bit, tourist numbers and travel costs decrease significantly.
 

Still Hot During Daytime

September marks the transition between summer and autumn: the weather cools down a little. The daytime highs drop from 31-38°C (88-100°F) in early September to 23-28°C (73-82°F) at the end of the month. However, most days in September remain hot, with daily highs frequently exceeding 35°C (95°F) and the highest temperature reaching 39°C (102°F), which usually occurs in the first half of the month. The downward trend can be seen until around the last 10 days of the month. Luckily, after sunset or on rainy days, the heat eases a lot, with lows of 16-27°C (61-81°F), making it suitable for outdoor explorations.

However, in certain years, September in Chongqing maintains its persistent heat with no sign of autumn cooling. For instance, in September 2024, daily highs consistently ranged between 32°C and 40°C (90-104°F).

Mountainous areas in Chongqing experience cooler temperatures than the urban districts. Take Wulong as an example, its daily highs range from 23°C to 31°C (73-88°C). In extreme cases, daily highs would drop as low as 17 degrees Celsius (63 degrees Fahrenheit).
 

City View after Rain

Chongqing in September experiences rich rainfall, with frequent rainy days. The average precipitation is 136 mm over 12 days. However, there’s no need to worry: September’s precipitation is mainly in the form of brief showers and nighttime rain, causing limited disruption to daytime activities. Plus, showers also bring a noticeable drop in temperature.

However, it’s worth noting that mountain areas would experience persistent heavy downpours. For instance, Dazu District received an accumulated precipitation of over 250 mm in September 2025. In addition, these heavy downpours are often accompanied by strong winds and lightning, which increases the risk of floods, mudslides, and other disasters. Therefore, it’s best to check the weather forecast frequently and avoid visiting mountainous regions during severe weather conditions but stay in urban areas.
 In September, Chongqing experiences a humid climate, with an average humidity level of 77%. Such a high-humidity climate would intensify the muggy feelings, especially in the first half month when the temperatures are higher. In contrast, on rainy days or in the suburbs with lower temperatures, the air feels much fresher and more comfortable.
 

Sunset View at Raffles City

Monthly Sunshine Hours: 103 hoursAverage UV Index: 10

Chongqing in September experiences limited sunshine hours, about 3 on average. Meanwhile, foggy days gradually increase, but heavy fog typically appears in the early morning. If you want to catch a clear skyline view, remember to check the weather forecast or arrange it in the afternoon when the fog disappears and the lights are soft.

The sunlight is still pretty intense with the average UV index of around 10, in which circumstances protection measures are necessary.