Climate and monthly weather forecast
Phonsavan, Laos

The geography of Phonsavan nests it within the cooler climatic belt of Laos. Designated as Cwa according to Köppen climate classification system, it exemplifies a humid subtropical climate with a dry winter. Over the entire year, the mercury primarily registers between 8.8°C (47.8°F) and 28.7°C (83.7°F).

Rainfall exhibits a wide range from 8mm (0.31") in driest month December, to an eyewatering 301mm (11.85") during the wettest month in August. The number of rainy days follows a similar pattern, the lowest number of days being 2 in January and December, reaching up to 22 during July and August. While rainfall increases, the amount of daylight hours rises from 11 to peak at 13.3 hours during the summer months, before receding towards the end of the year.

A distinct characteristic of Phonsavan's climate is its inverse relationship between rainfall and temperature. As one would expect, the months with minimal rainfall, namely December and January, generally tend to be cooler, while the months with most precipitation like August, coincide with sultrier temperatures.

Spring, from March to May, is arguably the best time to visit Phonsavan. During this period, daily highs average between 28.1°C (82.6°F) to 28.7°C (83.7°F), resulting in warm yet comfortable weather. With rainfall moderately escalating from 57mm (2.24") to 194mm (7.64") and daylight hours gradually increasing from 12 to 13.1 hours, it offers a pleasant balance of sunshine and occasional showers enhancing the landscape's lush greenery.

The period from June to August is considered unfavorable for planning a visit to Phonsavan. This season witnesses the highest rainfall ranging from 193mm (7.6") to 301mm (11.85"), with daily showers on 20 to 22 days of the month. Moreover, with temperatures hovering between 26.7°C (80.1°F) to 26.5°C (79.7°F), a perpetual veneer of humidity paints both the days and the nights.

Weather in Phonsavan during spring from March to May, presents a warming trend, with maximum temperatures ranging from 28.1°C (82.6°F) in March to a noteworthy 28.7°C (83.7°F) in May. Concurrently, the minimum temperatures follow suit, amplifying from 14°C (57.2°F) to 19°C (66.2°F). Rainfall marks a clear upward trajectory, from a mere 57mm (2.24") in March to reach 194mm (7.64") in May. Warming temperatures and increasing rainfall encapsulates spring, manifesting a vibrant and verdant landscape with over 12 hours of daylight.

Summer in Phonsavan stretches from June to August offering generous daylight hours, topping at 13.3 in June. This light-filled period, albeit benevolent, brings with it escalating rains with precipitations ranging between 193mm (7.6") in June to a voluminous 301mm (11.85") by August. Amidst these showers, the mercury maintains a relatively steady range of 27.2°C (81°F) to 26.5°C (79.7°F), weaving a moist, albeit warm, ambiance around the city.

Autumn months from September to November, see a decline in rainfall from 158mm (6.22") to a lighter 23mm (0.91"), together with a reduction in rainy days from 16 to 4. The temperatures remain steady, with highs from 26.6°C (79.9°F) dipping to 23.8°C (74.8°F) while the lows drop from 17.8°C (64°F) to 11.6°C (52.9°F). Daylight hours gradually diminish from 12.3 in September to 11.2 by the end of November, painting an exquisite canvas enwrapped in the soothing hues of autumn.

Winter in Phonsavan is recognized as the driest season with an average total precipitation from 23mm (0.91") in November plummeting to only 8mm (0.31") in December. The number of rainy days dwindles, oscillating between 4 in November reaching the yearly low of 2 in December. Though the daylight hours decrease to the annual minimum of 11 hours, temperatures remain comfortably cool. Winter highs and lows steadily lessen, sustaining a temperature range from 21.7°C (71.1°F) in December to 8.8°C (47.8°F) in January. Phonsavan's winter manifests as a tranquil respite from the bustling rains of the summer and paints an appealing portrait of serenity.

The calm winter period in Phonsavan, Laos, offers mild weather conditions. Following the steady decline in temperature from December, January has the lowest average temperature with highs reaching up to 23.3°C (73.9°F) and lows dropping to 8.8°C (47.8°F). Weather in January »

As February sets in, Phonsavan begins to witness a slight rise in temperature. With temperatures climbing slightly from the previous month, this transition period offers a comfortable blend of cooler mornings and warmer afternoons. Weather in February »

March in Phonsavan signifies the onset of spring, with evident changes observed in weather conditions. In comparison to February, the high temperature sees an increase, hovering around 28.1°C (82.6°F). This increase in temperature accompanies a notable rise in the amount of rainfall recorded, yet it’s a month of relative comfort. Weather in March »

April is a month of significant transformation in Phonsavan, showing the gradual transition into the hotter segment of the year. The temperature surge in April, peaking at 28.7°C (83.7°F), brings to the city, the year's highest recorded temperatures. Weather in April »

May in Phonsavan is characterized by the consolidation of the city's summer season. A decline in temperatures from the highs of April coincides with the monsoon showers ushering in substantial coolness. The city witnesses a rise in rainfall levels, making it the wettest month so far. Weather in May »

June marks the middle of the year in Phonsavan, bringing along with it a medley of weather conditions. Temperature fluctuations between May and June are almost indiscernible, showing a near-constant trend. Rainfall records a slight increase, falling in fairly evenly distributed showers throughout the month. Weather in June »

July, in the heart of the monsoon, sees the highest rainfall recorded in Phonsavan with a peak at 277mm (10.91"). The cool showers in tandem with the steady temperatures make this month a quite pleasant time in the city. Between June and July, daylight hours drop slightly yet offer abundant sunshine to offset the showers. Weather in July »

August in Phonsavan characterizes persistent rainfall, surpassing the previous record from July to reach 301mm (11.85"). Conforming to the summer trend, the temperatures remain steady and do not stray far from the regular range. Weather in August »

With the beginning of fall, September in Phonsavan witnesses a departure from the extreme weather conditions of the summer months. The temperatures remain consistent with the year's pattern but rainfall shows a significant decline, indicating the departure of the monsoon. Weather in September »

October denotes the beginning of the end of the high rainfall days, serving as a transitional period in Phonsavan. Even as temperatures climb slightly, October brings in pleasant days with considerably lower rainfall than in September. Weather in October »

November in Phonsavan denotes a visible shift towards winter, characterized by a notable drop in temperature and rainfall. Precipitation is at its lowest since the start of the year with only 23mm (0.91"), signifying the onset of the drier months. Weather in November »

December in Phonsavan signifies the commencement of winter, with coolness defining the city's weather. Following the trend of November, the month continues to experience lower temperatures. The continuation of low precipitation paints a clear, sunny picture for the city. Weather in December »