Investigators from Hang Dong Police Station in Chiang Mai, working with officers from Chang Phueak Police Station and other units, arrested three suspects at a second-hand goods shop in Chang Phueak subdistrict, Muang district, Chiang Mai on August 18. The arrests followed a tip-off about theft of water pumps in the Hang Dong area, leading police to track down the group attempting to sell stolen goods.

The three suspects are Chai, 20; Moo, 21; and A (alias), 15. During interrogation, they admitted to stealing not only water pumps but also electrical wiring from an abandoned hotel in Chang Phueak subdistrict. They would cut the wire and use a ride-hailing app to have it transported to second-hand shops. On August 16, they sold over 100 kilograms of wire, and were attempting to sell an additional 40 kilograms when police apprehended them with the stolen goods.

Police examining the suspects' mobile phones discovered videos showing the group cutting electrical wire inside the abandoned hotel while rap-singing hip-hop lyrics, proudly showcasing their crimes. The suspects also revealed that while stealing at the hotel, they encountered another theft gang stealing electrical appliances. The two groups negotiated and agreed to divide the area to avoid conflict before police arrested them and filed criminal charges.

A cooking gas cylinder exploded inside a row of apartments in the Mae Hia neighborhood of Chiang Mai on August 18, 2025, at around 6 p.m., when a woman opened the gas to reheat food. The explosion erupted in flames, causing serious injuries. Chiang Mai Provincial Police received the report and officers from Chiang Mai City Station rushed to the scene. One woman was found with severe burn injuries to her face and throughout her body from the blast. Medical emergency personnel, the Chiang Mai Traffic Safety Center, the Phetchkasem Foundation, rescue workers, and ambulances were called to provide immediate assistance before transporting the victim to the hospital for emergency medical care. When questioned, the injured woman reported that she was about to reheat her food when she opened the gas, and the explosion occurred immediately. The exact cause of the explosion remains under investigation, with police and related agencies conducting a detailed examination of the scene and further investigation into the cause.

Thailand's national football team lost 1-2 at home to Singapore on August 18, 2025, in the second leg of the AFF Cup 2026 semifinal at Rajamangala Stadium, but advanced to the final on aggregate score of 4-3. Thailand had won the first leg 3-1 away in Singapore and held the advantage coming into this match.

Head coach Anthony Hudson made six player changes from the previous game. Thailand's starting lineup included Kampol Pathamarkkul, Pansa Hemviboonlert, Manuel Tom Bihr, Seksarn Ratree, Sarawut Yooyean (captain), Worachit Kanitsribampoen, Theerasak Phaiyimai, Narubadin Weeravatwanoddom, Picha Uthra, Wanchai Charunograran, and Patrick Gustavsson.

Singapore, needing goals, attacked from the start while Thailand sat deep and looked for counterattacking chances. In the 45th minute, Singapore took the lead 1-0 when Harrish Stewart converted a long ball after goalkeeper Kampol misdirected it, making the aggregate score 1-2.

In the 62nd minute, Thailand equalized from the penalty spot after Wanchai Charunograran was fouled by Riyahan Stewart. Kunkana Kamyok scored the penalty to level the second leg 1-1, bringing the aggregate to 4-2. Singapore regained the lead 2-1 in the 65th minute when Riyahan Stewart scored after collecting a loose ball, making the aggregate 4-3.

No further goals were scored. Thailand lost the second leg 1-2 but won the two-leg tie 4-3 on aggregate and secured a place in the AFF Cup final.

On August 18, 2025, Metropolitan Police Bureau officials raided a distribution center in the Pathumwan area of Bangkok following intelligence about illegal transport of counterfeit allergy medicine branded "Allergin Syrub." Officers inspected a box truck at the distribution point and discovered brown bottles with blue labels packed in 103 cardboard cases, totaling approximately 20,000 units ready for shipment to southern Thailand.

The operation resulted from sustained investigation by Bangkok Metropolitan Police. Officers tracked the merchandise distribution route and identified the driver, Somkiat, who was transporting the products for a company. Authorities are pursuing charges against him and expanding the investigation to include upstream suppliers and all involved parties.

Initial examination confirmed the syrup as counterfeit and revealed it was being used as an ingredient in bootleg herbal remedies labeled "4×100." Police are coordinating with the legitimate product owner to verify the counterfeiting and prepare charges under pharmaceutical law, trademark law, and related statutes.

Investigators determined the smuggling operation has been running for approximately one month, with shipments sent to multiple southern provinces and Phuket receiving particularly large quantities. The seized batch alone exceeds 20,000 bottles worth approximately 1.4 million baht at the street price of 70 baht per bottle. If daily shipments averaged 10,000 bottles over the month-long operation, total circulation could exceed 300,000 bottles.

Police warn anyone using counterfeit allergy products to mix with herbal remedies to exercise caution, as the seized goods pose potential health risks to consumers. Authorities are intensifying efforts to apprehend additional suspects, particularly those controlling the supply chain and distribution network operating in southern Thailand.

The Northern Thailand Meteorological Center has issued a weather warning for severe monsoon conditions affecting the northern region from August 18–23, with the heaviest rainfall expected on August 19–21. Director Prasert Purathanang announced the forecast at a Chiang Mai media briefing, noting that thunderstorms will affect 60–80 percent of the northern region, with some areas experiencing continuous heavy rainfall. Temperatures will range from 20–29°C at night to 28–35°C during the day, with southwesterly winds at 10–20 kilometers per hour.

The severe weather is caused by a monsoon trough passing over the northern and upper northeastern regions, combined with a strong southwest monsoon over the Andaman Sea and Gulf of Thailand. Residents in low-lying areas, foothill zones, and high-risk areas are warned to be prepared for flash floods, river flooding, and landslides. The meteorological center urges the public to closely monitor weather forecasts and official warnings, avoid travel through flooded areas, and those in at-risk zones should move valuables to higher ground.

Looking ahead, the northern region is expected to experience intermittent heavy rainfall through August and September due to the continued influence of the monsoon trough and southwest monsoon, with a possible impact from tropical cyclones. August is forecast to see 190–230 millimeters of rainfall across the north, about 10 percent below normal, while Chiang Mai will receive 150–200 millimeters. September is projected to have 160–200 millimeters regionally, 20 percent below normal. Year-to-date rainfall in the north stands at 581.9 millimeters, significantly less than the 1,604.5 millimeters recorded during the same period in 2024.