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Thailand Weather: July 5 — Heavy Rain and Rough Seas Nationwide
Thailand is under significant weather pressure today, July 5, 2026, with the Thai Meteorological Department warning of heavy to very heavy rain across most regions. A monsoon trough feeding into Tropical Storm Maysak is driving strong southwest winds across both the Andaman Sea and the Gulf of Thailand, pushing up waves and grounding small boats along the west coast. Travellers around Koh Lanta, Krabi, and Phuket should treat today as a shore day.
Andaman Sea (Koh Lanta, Krabi, Phuket)
Conditions are at their roughest on the upper Andaman Sea, where waves are running 2-3 metres and can exceed 3 metres in storms. Small boats have been ordered to stay in port. All vessels are advised to steer clear of thundery patches. Diving, snorkelling, and island-hopping trips from Koh Lanta, Krabi, and Phuket carry high risk today, and operators are likely to cancel departures. The lower Andaman Sea sees waves around 2 metres, also exceeding that in storms.
Gulf of Thailand East Coast (Koh Samui Side)
Storm coverage on the southern east coast is lower at around 30%, but offshore waves are still 1-2 metres or more. Phetchaburi, Prachuap Khiri Khan, and Narathiwat are flagged for heavy rain. Winds are running 15-35 km/h. Conditions are calmer than the Andaman, but still worth watching before heading out on the water.
Northern Thailand (Chiang Mai, Mae Hong Son)
A 70% storm probability covers the north today. Mae Hong Son, Chiang Mai, Lampang, Phayao, Phrae, Uttaradit, Phitsanulok, and Phetchabun are all in for heavy rain. Tak and Chiang Rai face very heavy rain. Flash flood warnings are in place for foothills, waterways, and low-lying land, so trekking and outdoor activities carry real risk. Road runoff near rivers is also a hazard for drivers.
Northeast Thailand
Similar picture in the northeast, with 70% storm coverage. Loei, Udon Thani, Sakon Nakhon, and Mukdahan face heavy rain, while Nong Khai, Bueng Kan, and Nakhon Phanom are flagged for very heavy rain. Flash flood risk applies here too, especially near rivers and low-lying areas.
Eastern Thailand (Pattaya, Koh Chang)
The east gets 70% storm probability as well, with heavy rain across Nakhon Nayok, Prachin Buri, Sa Kaeo, Chachoengsao, Chon Buri, and Rayong. Chanthaburi and Trat face very heavy rain. Coastal seas are rough, and winds are stronger here at 20-35 km/h. Travellers in the Pattaya and Koh Chang corridor should expect disrupted boat services and stay alert on coastal roads.
Central Thailand
Central Thailand sits at 60% storm coverage, with heavy rain in Ratchaburi and Uthai Thani and very heavy rain possible in Kanchanaburi. Winds reach 10-25 km/h from the southwest.
Quick Reference by Region
| Region | Storm Chance | Notable Rain Areas | Temp | |---|---|---|---| | North | 70% | Chiang Mai, Tak, Chiang Rai | 23-34°C | | Northeast | 70% | Nong Khai, Nakhon Phanom | 23-34°C | | Central | 60% | Kanchanaburi | 24-35°C | | East | 70% | Chanthaburi, Trat | 24-32°C | | South (east coast) | 30% | Phetchaburi, Narathiwat | 23-35°C |
Information sourced from The Thaiger.