Steady, moderate rain fell on Bangkok and surrounding provinces throughout early Monday morning and into the rush-hours, causing traffic congestion across the capital on the first working day of the week.
Traffic jams were reported via the Facebook pages of traffic radios FM91Trafficpro and JS100. Several accidents added to motorists' problems.
Stalled commuters used social media to vent their fustrations, complaining it was taking much longer than usual to reach their destinations.
The weather radar operated by Bangkok Metropolitan Administration reported at 8am the rain was slowly stopping in Bangkok, Samut Prakan and Samut Sakhon, Nonthaburi and Pathum Thani. The BMA reported that highest rainfall recorded was in Bang Khun Thien district, with 54.5 millimetres.
The Meteorological Department on Monday morning warned of summer storms continuing from Monday to Wednesday in all regions.
Variable weather was forecast with the possibility of summer storms and hail in parts of the North, the lower Northeast, the Central and the East of Thailand. Southern Thailand will see more rain.
People are advised to beware of the "severe weather conditions" when outdoors.
The Nakhon Ratchasima municipal area was pelted by heavy rain for about one hour on Sunday night, starting about 7pm. Many spots in the municipality were covered with water up to 30 centimetres deep.
They included areas in front of the Save One Market and The Mall department store on Mitraphap Road, the Wat Mai Ampawan intersection on Mukkha Montree Road, the IT Plaza intersection on Ratchadamnern Road and Det-udom Road.
Municipal workers were sent to clear garbage that was blocking drains and preventing the water draining off. The roads were later reported to have dried out.