Monthly weather forecast and climate

Flag of Laos
Flag of Laos

The climate of Laos

Laos has a mainly tropical climate, with landlocked geography in Southeast Asia. Significant portions of the western and southern regions experience a tropical savannah climate (Köppen climate classification Aw). A large strip from the west-central to the southeast region falls under the influence of the tropical monsoon (Köppen Am). The remaining one-third of the land in the north and east has a subtropical climate (Köppen Cwa, Cwb). Laos lies at the center of the Indochinese Peninsula. Vietnam lies in the east, Cambodia in the southeast, Thailand in the southwest and west, and Myanmar and China in the northwest. The latitudes, high mountains, and monsoonal rains influence the climate.

Laos is a tropical country between latitudes 14°N and 23°N, with a northwest-southeast orientation. The topography is mainly mountainous, with steep terrain. The Annamite Range stretches from northeast to east, while the Luang Prabang Range lies in the northwest. The northern region is mountainous, with elevations mostly above 500 meters, and narrow river valleys. The Xiangkhoang Plateau in the north consists of green mountains and fertile valleys with numerous rivers. The Bolaven Plateau in the south has an average elevation of 1000 to 1350 meters. The panhandle region in the south consists of large level areas. However, only 4% of the land area is arable. The Mekong River is the largest and marks much of the western border with Thailand. The Annamite Chain forms the eastern boundary with Vietnam. Phou Bia is the tallest peak in Laos with a height of 2818 meters above sea level.

Summers are hot, and winters are chilly in Laos. March to mid-May is the hottest period of the year. The average high temperatures reach a peak of 35°C (95°F) in April. Temperatures reach up to 42.2°C (108°F) in the center-south and 45°C (113°F) in the north. The days have high temperatures, but even the nights can be warm and oppressive. The Luang Prabang region in the north has a relatively mild climate, with warm to hot summers and cold winters. Frost is common in the highlands and mountains. The southern region has harsh summers and mild winters. The mountainous regions are wetter than the plains, particularly at an altitude above 1000 meters. The rainy season begins by mid-May and stretches up to October. November to February is cold and dry in the winter. The average low temperatures are in the 10°C (50°F) to 15.6°C (60.1°F) range at the peak of the cold season. Temperatures vary by altitude and are significantly lower in the mountains and uplands than the plains.

The annual rainfall in Laos ranges from 1270mm (50") to 1778mm (70") in the plains and exceeds 3048mm (120") on the high mountain slopes. The Bolaven Plateau receives the highest rainfall of 3810mm (150") annually. The Luang Prabang region sees an average of 159 wet days in the year. Vientiane, the capital in the center-south, registers 118 rainy days annually. August and September are the wettest months due to the additional effect of typhoons. December is the driest month. The annual sunshine is ample and registers between 2100 hours in the north to 2600 hours in the south. The daily sunshine lasts for 8 hours in the center-south and 9 hours in the far south in the winter. The monthly average relative humidity ranges from low 66% in March to a high of 84% in August. The sun's ultraviolet index remains in the dangerous zone of 11 to 12 throughout the year except for the moderate winter months.

The highest temperature on record for Vientiane is 41.1°C (106°F), while the record for the lowest temperature is 0°C (32°F).

The best time to visit Laos

The best time to visit Laos is from November to February in the mild winter season. December and January are particularly pleasant, with comfortable temperatures in the average range of 10°C (50°F) to 29.4°C (84.9°F). The usually intense sunshine is moderately strong in the winter months. Tropical storms may linger until November, while temperatures exceed 35°C (95°F) in February in many regions. The northeast monsoon is active during the winter months. However, the rainfall is modest, and the sunshine is adequate between 6 hours and 9 hours. Nights are cozy on the plains, but cold in the mountains and highlands.

The worst time to visit Laos

The worst time to visit Laos is from June to August in the wet season. The southwest monsoon contributes much of the annual rainfall, and the atmosphere is humid and hot. Cloudy skies rule the roost. The heat index is high, and the rainfall is heavy. Rainstorms frequently occur in the wet months. Each month of the rainy season has at least 18 wet days and receives more than 254mm (10") of rain. Road travel becomes difficult, especially in the highlands where cloudbursts can occur. Typhoons frequently occur between August and October and bring heavy precipitation.

Weather hazards

Laos faces weather hazards like thunderstorms, floods, droughts, tropical storms, typhoons, and earthquakes. Thunderstorms and rainstorms frequently occur in the rainy season. Heavy rainfall significantly increases the risk of floods and mudslides. Droughts are frequent in the interior in the summer. Tropical cyclones of Southeast Asia often affect Laos between May and December. Typhoons from the South China Sea hit the northern parts of Laos more than the southern regions. Tropical storms from the Bay of Bengal reach as far as Laos, with sustained high wind speeds. The mountainous region is prone to seismic disturbances, although earthquakes of large magnitudes are rare.

Weather in January

January is mild to cold in the winter in Laos, with plenty of sunshine. Luang Prabang has cool average temperatures in the 13.9°C (57°F) to 27.8°C (82°F) range, with cloudy skies and dull weather. Days can be hot, even in the mountains. Weather in January »

Weather in February

February is a mild winter month in Laos, with 7 hours to 9 hours of daily sunshine. Luang Prabang is between 15°C (59°F) and 31.1°C (88°F), with warm days and cozy nights. Vientiane and Savannakhet register warm temperatures between 17.8°C (64°F) and 31.1°C (88°F). Weather in February »

Weather in March

March is hot and dry in Laos at the end of the mild winter season. In Vientiane and Savannakhet, on the western boundary along the Mekong River, the average temperatures are in the hot range between 22.2°C (72°F) and 33.9°C (93°F). Weather in March »

Weather in April

April is usually the hottest month in the summer of Laos, with average high temperatures between 29.4°C (84.9°F) and 35°C (95°F). Luang Prabang registers average temperatures in the 21.1°C (70°F) to 35°C (95°F) range, while Attapu in the southeast is in the hot 25°C (77°F) to 35.6°C (96.1°F) range. Weather in April »

Weather in May

May is hot, humid, and cloudy in Laos. The skies are overcast for 70% to 85% of the time. The heat index increases significantly with the relative humidity between 75% and 80%. The daily sunshine reduces to less than 6 hours, and the daylight lasts for 13 hours. Luang Prabang is considerably hot, with average temperatures in the 22.8°C (73°F) to 33.9°C (93°F) zone. Weather in May »

Weather in June

June is humid, cloudy, and wet in Laos with the arrival of the southwest monsoon. The skies remain overcast for 90% of the time. The daily sunshine lasts hardly for 5 hours in much of Laos. June 20 is the longest day of the year in Vientiane, with 13 hours and 12 minutes of daylight. Weather in June »

Weather in July

July is humid and wet in Laos, as the wet season brings abundant rainfall everywhere. Thunderstorms frequently occur, and heavy spells of rain often make roads impassable. The northern mountainous regions receive up to 228.6mm (9") of rainfall. Luang Prabang is hot and muggy between 23.9°C (75°F) and 32.2°C (90°F), with 4 hours of daily sunshine. Weather in July »

Weather in August

August is the wettest month of the year in Laos, with mostly cloudy skies and high humidity. In the north, Luang Prabang receives 226.1mm (8.9") of heavy rainfall, while Vientiane records a massive 335.3mm (13.2") in the south. August sees at least 20 wet days, partially due to the effect of typhoons. Weather in August »

Weather in September

September is hot, humid, and rainy in Laos, with mostly cloudy skies. However, the sun's ultraviolet index is at a peak of 12, even in the wet month. The daily sunshine lasts for 5 hours in the south and 6 hours in the north. Weather in September »

Weather in October

October sees reduced heat and humidity at the end of the rainy season in Laos. The precipitation reduces significantly to register 76.2mm (3") in the south and 101.6mm (4") in the north. October sees up to 8 wet days, with the relative humidity in the 60% to 75% range. The northern mountain region registers average temperatures in the comfortable 15.6°C (60.1°F) and 23.9°C (75°F). Weather in October »

Weather in November

November is warm and relatively dry in Laos after the return of the southwest monsoon. The skies remain clear up to 60% of the time, and the daily sunshine lasts for 6 hours to 8 hours. The daylight decreases from 11.5 hours to register slightly more than 11 hours by the end of the month. The northern mountain regions of Phongsali and Xam Nua experience warm days and cold nights as the average temperatures register in the 10°C (50°F) to 21.1°C (70°F) range. Weather in November »

Weather in December

December is the beginning of the mild to cold winter in Laos. The atmosphere becomes pleasant due to the drop in humidity and temperatures. The average temperatures in Vientiane register in the mild 17.2°C (63°F) to 27.8°C (82°F) range, while Attapu is between 20°C (68°F) to 29.4°C (84.9°F). Weather in December »