The National Water Resources Office (สทนช.) warns of heavy rain from 29 Aug to 2 Sep 2026 in 18 risk provinces, including Chiang Mai, Chiang Rai, Nan, Phayao, Phitsanulok, Khon Kaen, Nakhon Ratchasima, Kanchanaburi, Chanthaburi, Trat, Phang Nga and Ranong. Flash floods, landslides and Mekong water-level rises are flagged. 22 medium and small reservoirs are above capacity, so releases may increase downstream. If your shop, warehouse, farm or transport route is in these provinces, check stock, equipment and delivery routes now. Official radar and rain updates are on the สทนช. website.