Lanzhou Weather in September

Season: early autumn
In short: cosy, dropping temperature, a bit rainy in the second half, some foggy days
Average temperature: 11 - 23℃ (52 - 73℉)

Lanzhou enjoys cosy weather in September on the whole. The temperature gradually decreases after mid-month, which serves as a typical feature of the transition period from summer to autumn.

In early to mid-September, the high temperature often remains at 20 - 28 degrees Celsius (68 - 82.4 degrees Fahrenheit), an ideal value for outdoor activities. It’s cool in the shade during the day, and only when the sun shines brightly at noon it is a little hot. At night, the temperature changes between 11 - 19℃ (51.8 - 66.2℉), dropping by 10 - 14℃ (50 - 57.2℉) from the daytime. There is no need to use the air conditioning when you return to the hotel after a day trip; just open the window, and then you can enjoy a comfortable night sleep. Occasional rainfall can also cool the air: the high temperature on rainy days drops to below 20℃ (68℉). But on the next sunny day, it goes back again. 

In late September, frequent visits of cold air prevent high temperatures from exceeding 20℃ (68℉). At the same time, the day-night temperature difference decreases due to increasing rainy or cloudy days.
 About 10 - 13 days are rainy this month, but the total precipitation is not high, 41 mm (1.61 in) on average. The rainfall is concentrated in mid to late September, and usually lasts for 2 - 3 days each time. Light rains and showers are the most common, with occasional heavy rains. The air humidity in Lanzhou in September increases to 66%, the highest of the year, and the climate can be considered relatively humid. 
 Only 3 - 5 days are completely sunny, while overcast or cloudy days dominate the month. In this case, the sunlight duration in Lanzhou is short: it can only receive about 6 hours of sunshine daily on average. UV index is still high on sunny days.

The sun rises at 6:36 - 6:58 and sets at 18:49 - 19:32, offering a daylight of about 12 hours, which is enough for Lanzhou day tours.
 Due to increasing humidity, fog appears 3 - 4 times in the early morning in September, and gradually dissipates after sunrise. Besides, strong winds, the cause of cold waves, pass by Lanzhou sometimes, with a maximum level of 4 - 5.
 (1) In early to mid-September
T-shirt and light jeans are suitable for sunny daytime. Shorts and skirts are not advised at all, unless you have a very robust body. Women who prefer long dresses need to wear leggings. When the night falls, add a thin jacket or short trench coat, particularly when you visit attractions along the Yellow River, like Zhongshan Bridge, Waterwheel Garden, and White Pagoda Park. Also, it’s enough to deal with possible rainy conditions. Lightweight casual shoes will not put pressure on your feet during long-term walking.

(2) In late September
A shirt or long-sleeve T-shirt and a thin hoodie are a good match. Also, carry a windbreaker with a removable inner layer to adjust in time in the face of dropping temperatures in the evening and on rainy days. Sweatpants and sneakers are advised, and leather boots are useful on rainy days.

(3) Other necessities
Sun hat, sunglasses, and sunscreen are advised to protect against strong UV rays when it’s sunny. Rain gear is needed, too. A raincoat is more advisable as it can be windy during the rainfall, making it unsafe to use an umbrella. If there is remaining space in your suitcase, put in some shoe covers for full protection. 
 1. Experiencing sheepskin rafting on the Yellow River is a must-do for many adventurers coming to Lanzhou in September 2026. It’s during the flood season, when water flows fast. Put on a raincoat or place a waterproof item such as a plastic bag before sitting down to prevent clothes from being splashed by river water. Besides, hold your phone firmly when taking photos in case it falls. A phone strap is useful. 

2. If you want to appreciate the Yellow River up close in a mild way, taking a cruise is a good option, especially at the sunset. Or you can take a leisurely stroll along the river bank.

3. It’s a low tourist season in Lanzhou, so you won’t be bothered by crowds when enjoying charming natural scenes and wonderful human landscapes at Gansu Provincial Museum, Bingling Temple, and Five Springs Park, and tasting various local food at Zhangye Road Pedestrian Street and Zhengning Road Night Market.

4. Be careful of high pollen in the air. For those who are allergic, try to avoid outdoor activities at dawn and dusk when pollen concentration reaches its peak. Besides, put on a protective mask to ensure respiratory health when going out, and carry anti-allergy medicine with you. Wash your hands, face, and nose, and change your clothes immediately upon going back to the hotel.