Laos has a tropical monsoon climate with strong seasonal contrast: a hot, wet season and a cooler, drier season. Most of the country is mountainous, so temperatures vary noticeably by elevation, with cooler conditions in the north and highlands and hotter conditions along the Mekong lowlands. Recent climate profiles describe annual rainfall of about 1,300 to 3,000 mm, with the wet season typically running from May to October and the dry season from November to April. For residents and expats, the climate is generally humid and rain-rich, with the main challenges being heat, heavy monsoon downpours, and flood risk in low-lying areas.