Laos in September

Our take: fair

Rain eases in the north, 195 mm in Luang Prabang against 313 in August, but stays heavy in the south. The Mekong is at its highest: the flood peak often comes in early September. It's still the green season.

By Pierre-Marie Coupry · updated October 13, 2026 · sources

Canoes on a sandy beach in a narrow valley between forested mountains — Photo by Ioana F on Unsplash

Laos weather in September, city by city

Luang Prabang in September

By day: 30°
At night: 23°
Rain: 195 mm
Rainy days: 23
The Mekong: High

Climate and Mekong water level in Luang Prabang, month by month
Month	J	F	M	A	M	J	J	A	S (current month)	O	N	D
Airhigh / low
Rainmm	20	10	35	82	142	179	288	313	195	71	23	20
Daysof rain	3	2	6	12	20	23	26	28	23	12	5	3
Mekonglevel	Low	Low	Low	Low	Low	Rising	Rising	High	High	Falling	Low	Low

Climate and Mekong water level in Luang Prabang, month by month
Month	mm	River
Jan	20	Low
Feb	10	Low
Mar	35	Low
Apr	82	Low
May	142	Low
Jun	179	Rising
Jul	288	Rising
Aug	313	High
Sep (current month)	195	High
Oct	71	Falling
Nov	23	Low
Dec	20	Low

Vientiane in September

By day: 30°
At night: 24°
Rain: 310 mm
Rainy days: 25
The Mekong: High

Climate and Mekong water level in Vientiane, month by month
Month	J	F	M	A	M	J	J	A	S (current month)	O	N	D
Airhigh / low
Rainmm	11	14	38	76	254	312	372	409	310	102	22	8
Daysof rain	2	2	6	12	23	25	27	28	25	12	3	1
Mekonglevel	Low	Low	Low	Low	Low	Rising	Rising	High	High	High	Falling	Low

Climate and Mekong water level in Vientiane, month by month
Month	mm	River
Jan	11	Low
Feb	14	Low
Mar	38	Low
Apr	76	Low
May	254	Low
Jun	312	Rising
Jul	372	Rising
Aug	409	High
Sep (current month)	310	High
Oct	102	High
Nov	22	Falling
Dec	8	Low

Pakse in September

By day: 29°
At night: 23°
Rain: 343 mm
Rainy days: 27
The Mekong: High

Climate and Mekong water level in Pakse, month by month
Month	J	F	M	A	M	J	J	A	S (current month)	O	N	D
Airhigh / low
Rainmm	2	4	25	54	191	315	446	451	343	138	36	6
Daysof rain	1	1	5	11	23	27	29	29	27	17	5	1
Mekonglevel	Low	Low	Low	Low	Low	Rising	Rising	High	High	High	Falling	Low

Climate and Mekong water level in Pakse, month by month
Month	mm	River
Jan	2	Low
Feb	4	Low
Mar	25	Low
Apr	54	Low
May	191	Low
Jun	315	Rising
Jul	446	Rising
Aug	451	High
Sep (current month)	343	High
Oct	138	High
Nov	36	Falling
Dec	6	Low

Air and rain: Open-Meteo, archive ERA5, 1991-2020 averages (retrieved October 11, 2026). Mekong level: Mekong River Commission, Pakse station, median of 2020-2025, 6.7 m between the lowest and highest months. The current month is outlined.

The Mekong in Laos in September

September is often the month of the flood peak: September 1, 2018 in Luang Prabang, September 3 in Vientiane, and Luang Prabang's record on September 2, 1966 (22.36 m), according to the Mekong River Commission. In September 2024, after Typhoon Yagi, the river rose above danger level in Luang Prabang.

Luang Prabang, at the confluence →

Luang Prabang at dawn from Mount Phousi: the muddy Mekong, rooftops and mountains in the mist — Photo by Basile Morin on Wikimedia Commons · CC BY-SA 4.0

Laos's September festival: Boun Khao Salak

Expected date in 2027 September 15 Temples across the country Full moon of the 10th lunar month. In 2026: September 26. In 2027, the full moon of the 10th month falls on September 15; the Lao date had not been published as of October 2026.

Two weeks after Khao Padap Din, the second festival of the dead: offerings to the monks for the departed in the morning, a candlelit procession in the evening.

Morning ceremonies start early: ask the temple for the time the day before.

Things to do in Laos in September

Children on the river rocks at Tad Lo, on the Bolaven Plateau — Photo by Corto Maltese 1999 on Wikimedia Commons · CC BY 2.0

Tad Suong and Tad Katamtok

Tad Suong, spectacular in the rainy season, and Tad Katamtok, in full flow all year round.

Bolaven Plateau

A Buddha draped in saffron before a wall of niches holding small statues, in a Vientiane temple — Photo by Rob te Braake on Unsplash

Khao Salak morning in Vientiane

Offerings for the dead at first light, two weeks after Khao Padap Din: ask the temple for the time the day before.

Vientiane

The Mekong at sunset between wooded hills in Bokeo province, Laos, on the slow boat route — Photo by Dick Hoskins on Pexels

The slow boat on a river in flood

The river at its highest and a strong current: check river conditions before you leave.

Huay Xai – Luang Prabang

The wide, brown Mekong seen from Mount Phousi in Luang Prabang, between wooded hills and mountains — Photo by Frank Eiffert on Unsplash

The Nam Khan confluence at its highest

The Mekong and the Nam Khan in flood, below the peninsula.

Luang Prabang

Planning for Laos in September

Floods: Levels can rise dramatically within hours: in September 2024, Luang Prabang went above danger level. Follow local alerts.
Crowds: The end of the green season, according to the tourism ministry: visitors return from November to January.
Packing: A rain jacket, quick-drying shoes and insect repellent.

Sources: climate, Open-Meteo (ERA5 archive, 1991-2020 averages); river levels, Mekong River Commission and Vientiane Times (September 2024); festivals, Tourism Laos calendar; 2027 dates, Kapook calendar; visitor numbers, 2024 statistics of the Lao tourism ministry; sights, KPL; safety and roads, FCDO. Updated October 13, 2026 by Pierre-Marie Coupry.