The Meteorological Department forecasts heavy rain over about 80% of Bangkok and its surrounding provinces for the next 24 hours, driven by cold air from China meeting the monsoon trough. Low-lying areas may flood briefly and disrupt travel, so expect slower deliveries and staff commuting delays, and avoid known flood-prone routes. Small boats in the upper Andaman Sea should stay in port until 20 Sep 2026 (BE 2569). Move stock off ground floors and check that outdoor work or events have a rain plan.