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Thailand Weather Forecast: July 4, 2026
Heavy rain is sweeping across most of Thailand today, driven by a monsoon trough over the North and Northeast linking up with Tropical Storm Maysak, plus a strong southwest monsoon pushing across the Andaman Sea, the mainland, and the Gulf of Thailand. The Thai Meteorological Department (TMD) has issued warnings for flash floods and runoff in low-lying areas and near mountain slopes. Whether you're planning a boat trip, a mountain hike, or a long drive, it's worth checking conditions before you head out.
What's Happening and Where
| Region | Storm coverage | Temperature range | |---|---|---| | North | 70% | 23-35 C | | Northeast | 70% | 23-35 C | | Central | 60% | 23-36 C | | East | 70% | 23-34 C | | South East Coast | 60% | 24-35 C | | South West Coast | 60% | — |
The Northeast is seeing some of the heaviest activity. Provinces around Nong Khai, Bueng Kan, and Nakhon Phanom are forecast for extremely heavy rain, while Loei, Udon Thani, Ubon Ratchathani, and several others are flagged for heavy rain. The East Coast is in a similar situation, with Chanthaburi and Trat at extremely heavy risk and strong winds of 20-35 km/h across the region.
Sea Conditions
Conditions on the water are rough, especially in the upper Andaman Sea where waves are running 2-3 metres and can exceed 3 metres during thunderstorms. The TMD is telling small boats in the upper Andaman Sea to stay docked today.
Elsewhere:
- Lower Andaman / upper Gulf of Thailand: around 2 m, higher during storms
- East coast near Chanthaburi and Trat: around 2 m, above 2 m in thunderstorms
- South east coast (north of Surat Thani): 1-2 m, above 2 m offshore during storms
- South east coast (south of Nakhon Si Thammarat): around 1 m, above 2 m in thunderstorms
All boats are advised to avoid thunderstorm areas regardless of size.
What This Means for Tourists
Koh Lanta / Krabi / Phang Nga / Ranong (West Coast): The southwest coast has 60% storm coverage and rough Andaman seas today. Water activities and ferry crossings carry real risk. Check with your operator before booking anything on the water.
Koh Samui area (South East Coast): Moderate risk. Offshore waves can exceed 2 m during storms.
Chiang Mai and the North: 70% storm coverage. Flash floods and runoff are a genuine concern on mountain roads and trails. Outdoor trekking plans should be reconsidered.
East Coast (Pattaya, Rayong, Koh Chang area): Some of the highest wind speeds today at 20-35 km/h, with extremely heavy rain possible near Trat. Ferry crossings to outer islands are not recommended.
Northeast and Central regions: Not primary tourist zones, but road flooding is likely if you're travelling through.
TMD Warnings
The TMD has specifically flagged flash floods and runoff in low-lying areas and near mountain slopes across affected regions. If you're in or near one of the provinces listed above, keep an eye on local conditions and avoid rivers, streams, and drainage channels after heavy rain.
Information sourced from The Thaiger.