Thursday, May 21st: Affected by the eastward movement of an upper-level trough, from tonight through tomorrow, cities and prefectures including Gannan, Linxia, Dingxi, Longnan, Tianshui, Pingliang, and Qingyang will experience a shift from cloudy to overcast skies with showers or sleet. Localized areas within Gannan, Dingxi, Longnan, Tianshui, Pingliang, and Qingyang will see moderate rain, while eastern Longnan, eastern Tianshui, eastern Pingliang, and southern Qingyang are forecast for moderate to heavy rain. Lanzhou and Baiyin will turn from cloudy to overcast with scattered showers. Other areas within the province will be cloudy, with the Qilian Mountain area overcast with showers or sleet. Additionally, cities including Jiuquan, Wuwei, Baiyin, and Lanzhou will experience northwest winds of force 4-5, accompanied by blowing dust. Influenced by a cold air mass, temperatures across most of the province will drop significantly from west to east on the 21st. It is advisable to add clothing promptly to guard against respiratory illnesses such as colds.

[Provincial Weather Forecast] Tonight through tomorrow (May 20, 20:00 - May 21, 20:00): Gannan, Linxia, Dingxi, Longnan, Tianshui, Pingliang, and Qingyang will see a change from cloudy to overcast with showers or sleet. Localized moderate rain is expected in Gannan, Dingxi, Longnan, Tianshui, Pingliang, and Qingyang, with moderate to heavy rain forecast for eastern Longnan, eastern Tianshui, eastern Pingliang, and southern Qingyang. Lanzhou and Baiyin will be cloudy to overcast with scattered showers. Other regions will be cloudy, with the Qilian Mountain area overcast with showers or sleet. Furthermore, Jiuquan, Wuwei, Baiyin, and Lanzhou will have northwest winds of force 4-5 with blowing dust. Due to the cold air, temperatures will fall notably across most areas from west to east on the 21st.

Tomorrow night through the day after (May 21, 20:00 - May 22, 20:00): Longnan, Tianshui, Pingliang, and Qingyang will be overcast with light rain, with moderate rain in eastern Longnan, eastern Tianshui, and southern Qingyang. Other parts of the province will be sunny or cloudy, with localized showers or sleet in parts of Gannan and Dingxi and the eastern Qilian Mountains.

Night of May 22nd through May 23rd (May 22, 20:00 - May 23, 20:00): Linxia, Gannan, Dingxi, Longnan, Tianshui, Pingliang, and Qingyang will turn from cloudy to overcast with showers, with localized moderate rain in Gannan, Dingxi, Tianshui, Pingliang, and Qingyang. Baiyin and Lanzhou will be partly cloudy to overcast with localized showers. Other areas will be sunny or cloudy, with the Qilian Mountain area overcast with showers or sleet.

[Three-Day Lanzhou Forecast] Night of the 20th to day of the 21st: Light floating dust turning to showers, temperatures 14°C to 25°C. Night of the 21st to day of the 22nd: Cloudy turning to sunny, temperatures 11°C to 28°C. Night of the 22nd to day of the 23rd: Cloudy turning to showers, temperatures 16°C to 27°C.

[Lanzhou Meteorological Index Forecast] Human Comfort Index: Level 3, uncomfortable. Dressing Index: Level 6, suitable for wearing short skirts, short suits, etc. UV Index: Level 3, moderate intensity; take protective measures when going out. Outdoor Sports Index: Level 2, not very suitable for exercise. Cold Index: Level 2, low incidence of colds. Car Washing Index: Level 4, not suitable for washing cars. Dryness Index: Level 3, moderate dryness; appropriate skincare and hydration are advised.