Storms ease but heat and thunder linger in Thailand

Thailand is beginning to see a slight easing of its recent bout of summer storms, but unsettled weather remains in place, with thunderstorms, gusty winds and isolated hail still expected in some areas through April 22, according to the Thai Meteorological Department.

Earlier in the period from April 16 to 20, upper Thailand experienced widespread summer storms, marked by thunderstorms, strong winds and hail in some locations, with isolated lightning strikes also reported. The system first affected the Northeast and East before spreading to the eastern parts of the Central region and the North.

The conditions were driven by a high-pressure system, or cold air mass, from China extending over the South China Sea. This strengthened southerly and south-easterly winds over the lower Northeast and the East, while much of upper Thailand remained hot to extremely hot.

From April 21 to 22, rainfall is expected to decrease overall, although isolated thunderstorms will persist. Daytime conditions will remain hot as the prevailing winds weaken.

South sees rain increase later

In the South, weather conditions are shifting in the opposite direction. Between April 16 and 18, only isolated thunderstorms were reported alongside hot daytime conditions, influenced by westerly winds over the Andaman Sea and upper Gulf of Thailand, combined with south-easterly winds over the lower Gulf.

However, from April 19 to 22, rainfall is expected to increase, with thunderstorms becoming more widespread as south-easterly winds strengthen across the Gulf, the South and the Andaman Sea.

Wave conditions in both the Gulf of Thailand and the Andaman Sea remain relatively mild, averaging around one metre, but could exceed two metres in areas experiencing thunderstorms.

Regional outlook

Across the North, hot to extremely hot weather dominates, with storms affecting 10–30% of areas between April 18 and 20, particularly in eastern parts of the region. Temperatures are forecast to reach highs of 36–42°C.

The Northeast faces more active conditions, with thunderstorms covering 20–40% of the region through April 20, alongside strong winds, hail and isolated heavy rain. Conditions ease slightly afterwards, though heat remains intense, with highs up to 41°C.

In the Central region, storms are expected to affect 10–30% of areas through April 20, mainly in the east, before easing. Temperatures could peak at 42°C.

The East sees a similar pattern, with storms covering 20–40% of areas earlier in the period, bringing strong winds and isolated hail, before dropping to 10–20% later. Seas remain moderate but rough in storm conditions.

Bangkok and surrounding areas are expected to remain hot, with scattered thunderstorms affecting 10–30% of the area through April 20, easing slightly afterwards but still present in some locations. Temperatures could reach up to 40°C.

Public warning

Authorities are urging people across Thailand to take precautions against both extreme heat and unstable weather.

Residents are advised to avoid prolonged outdoor activity during peak heat, while those in upper Thailand should stay clear of open areas, large trees and unstable structures during storms.

Farmers are also encouraged to reinforce crops and prepare for potential damage from strong winds and hail, while mariners in both the Gulf and the Andaman Sea are warned to avoid sailing during thunderstorms throughout the period.