Latest weather update at 5pm: Summer storms to batter upper Thailand until April 20

Meteorological Department has issued its ninth warning of 2026, cautioning that summer storms will continue to affect large parts of upper Thailand through April 20, bringing a combination of heavy rain, strong winds and extreme heat.

According to the latest advisory issued at 5pm on April 18, widespread summer storms are expected across the North, Northeast, Central Plains and East. The most severe impacts are forecast in the Northeast and eastern regions, where thunderstorms, gusty winds, hail and isolated heavy downpours are likely. Some areas may also experience lightning strikes.

The unstable weather is being driven by southerly and south-easterly winds carrying moisture from the Gulf of Thailand and the South China Sea over upper Thailand, while the country continues to experience hot to extremely hot conditions.

Authorities have urged residents in affected areas to take precautions against sudden storms. People are advised to avoid open spaces, large trees and unstable structures or billboards. Farmers have been told to reinforce fruit trees and prepare measures to protect crops and livestock from potential damage. The public is also encouraged to take care of their health amid rapidly changing weather conditions.

In its 24-hour forecast, the department said upper Thailand would continue to see scattered summer storms, while the South will remain hot during the day with isolated thunderstorms due to easterly and south-easterly winds over the Gulf, the southern region and the Andaman Sea.

Air quality remains another concern, particularly in the North, upper Northeast and upper Central regions, where dust and haze levels have exceeded safe standards due to the accumulation of hotspots and limited air circulation. Residents are advised to avoid prolonged outdoor exposure and wear N95 masks when outside.

Regionally, the North is expected to see hot to extremely hot weather with daytime haze and isolated storms affecting about 10% of the area, particularly in provinces such as Mae Hong Son, Chiang Mai and Chiang Rai. Temperatures are forecast to range from 21–28°C at night to highs of 36–42°C.

The Northeast will experience hot conditions, with some areas reaching extreme heat. Storms are expected across around 40% of the region, with risks of heavy rain, strong winds and hail in provinces including Khon Kaen, Udon Thani and Nakhon Ratchasima. Temperatures will range from 22–27°C to 37–40°C.

In the Central region, hot to extremely hot conditions will persist, with storms covering about 20% of the area, mainly in Lopburi, Saraburi and Ayutthaya. Temperatures are forecast at 25–28°C to 38–41°C.

The East will remain hot with storms affecting about 30% of the area, particularly in Chonburi, Rayong and Chanthaburi, alongside rougher seas in storm-hit zones.

In the South, both coasts will see hot daytime conditions with isolated thunderstorms, while wave heights are expected to reach around one metre, rising above that in stormy areas.

Bangkok and its surrounding areas will experience generally hot weather with hazy conditions during the day and a 20% chance of thunderstorms, along with occasional strong winds. Temperatures are forecast between 26–29°C and 35–39°C.

Authorities continue to urge the public to remain vigilant as the combination of extreme heat, storms and poor air quality poses risks to health, agriculture and daily life.