Due to the complex geography and the greatly different elevation, the weather differs in different parts of Gansu. The climate in Gansu is dry, and the there is big difference in temperature between day and night. Because of the strong solar radiation, travelers in Gansu need to pay more attention on sun protection. The average temperature for a year is around 7 °C (45 °F). Generally speaking, the lowest temperature occurs in January with the temperature is from -14 °C (7 °F) to 3 °C (37 °F), and the highest temperature (from 22 °C or 72 °F to 25 °C or 77 °F) is in July. The rainy days mainly center in months from June to September. Dunhuang has the most sunlight, so the melons and fruits produced in Dunhuang are particularly sweet.
Due to the changeful weather, travelers intend to visit Gansu need to bring coat to keep out the cold in the morning and night besides some tourist necessities like sunscreen, sunglasses, hat and umbrella. The best time to visit Gansu is from May to October, even though the weather is changeable. The main tourist resource in Gannan Tibetan Autonomous Prefecture (甘南藏族自治州) is natural grassland, and the grass is the most luxuriant in summer, so summer (April, May and June) is the best season to travel in Gannan every year.