Long An's Climate
Long An is where the outskirts of Ho Chi Minh City dissolve into the flooded plains of the Mekong Delta, and its weather follows the classic sub-equatorial monsoon script: hot all year, no winter, and a calendar split cleanly into a wet half and a dry half. Everything here — the rice fields of Tan Hung and Vinh Hung, the dragon fruit orchards of Chau Thanh, the seedless-lime groves around Ben Luc — moves to that two-season rhythm.
Two seasons along the Vam Co rivers
The province collects about 2,301 mm of rain a year, almost all of it between May and November when the southwest monsoon sets in. Showers are typically short, intense afternoon downpours; September is the peak, with around 406 mm falling on nearly every day of the month. From December through April the skies clear and dry heat settles over the twin Vam Co Dong and Vam Co Tay rivers — harvest and drying season for farmers across the province.
Heat and salt at the tail of the dry season
April is the fiercest month, with average highs of 33.6°C and stretches of heat that crack the acid-sulfate soils of the Plain of Reeds and leave canals bone dry. It is also when the sea pushes back: salt water rides the tides up both Vam Co rivers into Can Duoc, Can Giuoc and Tan Tru, in some years reaching Ben Luc and Thu Thua. Orchard owners store fresh water in ponds before Tet and track the tides daily to keep their dragon fruit and limes irrigated through the saltiest weeks.
The floating season in the Plain of Reeds
From roughly September to November, floodwater from the upper Mekong spills across the border and turns Tan Hung, Vinh Hung and Moc Hoa into a shallow inland sea. Locals treat it less as a disaster than as a harvest: linh fish and sesbania flowers arrive with the water, and the cajuput forests of Tan Lap floating village and the Lang Sen wetland reserve are at their most beautiful for paddling and birdwatching. The early wet season in May–June does bring violent thunderstorms and lightning over open fields, and high tides in October–November can briefly flood low riverside neighborhoods near the city fringe.
When to go and what to pack
December to February is the most comfortable window — dry days and cool early mornings, with January lows averaging just 22.1°C, light-jacket weather at most. Come in September–November to paddle through flooded cajuput forest, and keep a compact raincoat handy since afternoon rain is near-daily. In the dry season, the treeless Plain of Reeds demands sunscreen, a wide-brimmed hat and plenty of drinking water; and in the lower districts of Can Giuoc and Can Duoc, tap water can taste faintly brackish on the saltiest days of April.