MANILA (AP) — Southeast Asia was coping with a weekslong heat wave on Monday as record-high temperatures led to school closings in several countries and urgent health warnings throughout the region.

Millions of students in all public schools across the Philippines were ordered to stay home Monday after authorities canceled in-person classes for two days. The main advice for everyone, everywhere has been to avoid outdoor activities and drink plenty of water, but the young and the elderly were told to be especially careful.

Cambodia this year is facing the highest temperatures in 170 years, Chan Yutha, a spokesperson for the Ministry of Water Resources and Meteorology, told The Associated Press on Monday. His agency has forecast that temperatures in most parts of the country could reach up to 43 degrees Celsius (109 degrees Fahrenheit) this week.