Het weer in Phnom-Penh in september

Regulars are direct that a forecast threatening rain every single day shouldn't be read as constant rain on the ground - a realistic day here is a sunny morning followed by two to three hours of rain in the afternoon or evening, the monsoon predictable and often preceded by a noticeable pickup in wind. Our row backs that hot, genuinely wet read, 34C reading as a hot 39C, over 25.4C nights, with a substantial 175.9mm of rain across nearly 26 days and humidity at 80 percent. Regulars are consistent this counts as heavy rainy season alongside July and September, though it won't rain non-stop, planning morning activities and keeping afternoons flexible is the standard local approach. The record: 9.3 hours of sun, a 14.7 kph wind and AQI 40.

March sits inside the hot season here, which runs roughly February to May, between the cool months and the rains that begin about June. The board does not pretend otherwise - by late March it is baking, dry and dusty, and April is worse. Our row gives 35.4C that reads as 40C, over nights holding 25C and feeling like 29C, so there is no cool half of the day to retreat into. Their working method is the useful part, and it is the same one every hot-season destination arrives at: out early, take the middle of the day in a pool or air conditioning, and start again late afternoon into the evening. Rain is 25.9mm across 4.7 days. The record: humidity 63 percent, 11.1 hours of sun and AQI 82.

November is the end of the wet season rather than part of the dry one, and regulars put the changeover at about the middle of the month - after which the dry season runs to February and the temperature eases slightly. Our row reads the first half: 122.4mm across 15.5 precipitation days, under 32C that feels like 37C at 81 percent humidity. So a trip in the last ten days of November is a different month from one in the first ten. The other thing to check before booking is the water festival, which falls in November on a lunar date that moves from year to year and fills the city when it lands. The record: 24.8C nights, 9.1 hours of sun, a 12.8 kph wind and AQI 49.

February closes Cambodia's dry season, and regulars name November through February as the perfect stretch - our row gives 13.5mm across 1.9 precipitation days, and their line is that if it rains at all it will be for under five minutes. What they warn about instead is what dry means on the ground: hot, humid and dusty, with months of no rain leaving the roads and the roadside powdery. In Phnom Penh that combines with traffic and construction into a genuine air-quality season from November to March, which our row puts at AQI 83. It is the coolest part of the year here in name only, at 33.4C reading as 37C. The record: 23.6C nights, humidity 62 percent and 10.6 hours of sun.