The climate of Sapa is unique to Vietnam. It is highly seasonal, with asubtropical climate in summer and a temperate climate during the winter. Thehottest months are May and June when temperature may goes up to 29°C and thecoldest months are December and January when temperature may drops down to 1°C.
In common with the rest of northern Vietnam, the wet season from May toSeptember, with the heaviest rainfall occurring in July and August. Humidityranges from 75 to 91 percent with a yearly average of 86 percent. Climate variesconsiderably within the nature reserve. The prevalent wind direction for most ofthe year is west to east, leading to cloud formation on the upper slopes of theFansipan massif. These high-altitude areas are covered by cloud most days of theyear and have very high humidity. Cloud also penetrates into the valleys butthese areas are usually less humid than the mountain slopes. In the extreme eastof the district, around Ban Ho village, mean temperatures are considerablyhigher due to the lower altitude of these areas.
There is a fact that the weather of Sapa is varied not only by months &seasons but also very different in localities due to the strong influences ofthe terrain and altitude. However below information may help to decide which isthe best time to go:
| Month | Weather features |
| January | Coldest month, cloudy, foggy butnot too wet. better from early days and gets worse to the later halfof the month. |
| February | Very cold in early days, cloudy,foggy. Getting warmer & better towards later days. |
| March | Much nicer and warmer than Feb, more sunshine |
| April | Summer start, dry, clear, warmenough |
| May | Starting rainy season with quickshower occasionally, clear sky with more sunshine but little bitwarm in the open at noon. |
| June | Warm but not as hot like otherregion. Clear sky, much sunshine but summer shower get more but nottoo wet |
| July | Among the 2 worst months of theyear caused by summer shower |
| August | The peak month of typhoon and rain |
| September | Autumn starts, getting drier andnormally very nice towards the end of the month. |
| October | Cool, dry, sunshine almosteveryday, clear sky |
| November | Cooler, dry. May be misty and foggytowards the end but nice |
| December | Wet winter starts and get worse atthe later days of the month. |
In reality, people say that “four seasons can be seen in a day” in Sapa thisis may be the best expression to describe the fast changes to weather here. Theweather in Sapa is unpredictable. It is nice, warm and clear to day and may berainy, wet and cold. So the above chart is just only a reference. For the monthswith worse weather, there is always some other good alternative options.