Sapa weather in September

In September, Sapa sees average daytime highs of 26°C and overnight lows near 20°C, with 202 mm of rain across 22.4 wet days and about 12.1 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 26°C through the month. The sky is clear or mostly clear about 14% of the time in September, and the air most often feels muggy.

Daylight stretches from about 12 h 30 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Sapa's 9th-clearest and 11th-windiest month. For the whole year in context, see Sapa's year-round climate.

Daytime high
26°
5th warmest
Overnight low
20°
9th coldest
Rainfall
202 mm
22.4 wet days
Daylight
12 h 06 min
5:55 AM – 6:03 PM
Cloud cover
74%
9th clearest
Wind
3 km/h
11th windiest
Solar energy
4.38 kWh/m²
Travel score
4.5
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in Sapa reaches about 26°C in the afternoon and slips back to 20°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 29°C. Set against its neighbours, September runs on par with August and about 2°C warmer than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12721
22721
32721
42721
52721
62720
72720
82720
92720
102720
112720
122720
132720
142720
152720
162620
172620
182620
192620
202620
212620
222620
232619
242619
252619
262619
272619
282619
292619
302619

Sapa weather by month

How September compares with the rest of the year at a glance. September is the 5th-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan18° / 10°8212.410.85.3
Feb19° / 11°731311.25.6
Mar23° / 14°13216.911.85.8
Apr25° / 17°17721.712.55.0
May27° / 20°23625.813.14.1
Jun27° / 21°34428.913.33.4
Jul27° / 21°39629.713.23.4
Aug27° / 21°38528.712.83.6
Sep26° / 20°20222.412.14.5
Oct24° / 18°10817.411.55.7
Nov22° / 14°6110.310.96.4
Dec18° / 11°631010.75.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 14% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 72%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12278
22179
32179
42278
52278
62278
72278
82476
92476
102476
112575
122575
132575
142773
152773
162773
172872
182971
193169
203169
213169
223367
233367
243466
253565
263664
273664
283763
293763
303763

Chance of precipitation in September

Any precipitation

Sapa gets around 202 mm of rain over 22.4 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 75% and peaks near 85% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%100%151015202530
Rain chance (%)
185
285
384
483
582
682
781
880
980
1079
1179
1278
1378
1477
1577
1676
1775
1874
1974
2073
2172
2270
2369
2468
2566
2665
2763
2862
2961
3060

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels muggy — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the muggy band about 71% of days. Sticky, muggy-or-worse air turns up on roughly 82% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
10037522
20037621
30147520
40157519
50167419
60167518
70177517
80287416
90287515
100297514
1102107513
1203107512
1303117511
1403127510
150413749
160413758
170414748
180515728
190516727
201517707
211618687
221619677
231720657
241721647
251722646
261823626
271824616
281825615
291926595
301927594

Wind in September

Winds average 3 km/h in September.

Across September, daily wind ranges from about 3 km/h on the calmest days to 3 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
13calm
23calm
33calm
43calm
53calm
63calm
73calm
83calm
93calm
103calm
113calm
123calm
133calm
143calm
153calm
163calm
173calm
183calm
193calm
203calm
213calm
223calm
233calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 30 min at the start of September to 11 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 42 minutes over September. Sunrise moves from 5:51 AM to 5:59 AM, and sunset from 6:18 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.55:516:18
212.45:516:17
312.45:516:16
412.45:526:15
512.45:526:14
612.35:526:13
712.35:536:12
812.35:536:11
912.35:536:10
1012.35:536:09
1112.25:546:08
1212.25:546:07
1312.25:546:06
1412.25:556:05
1512.15:556:04
1612.15:556:03
1712.15:556:02
1812.15:566:01
1912.15:566:00
2012.05:565:59
2112.05:575:58
2212.05:575:57
2312.05:575:56
2412.05:575:55
2511.95:585:53
2611.95:585:52
2711.95:585:51
2811.95:595:50
2911.85:595:49
3011.85:595:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.38 kWh/m².

For context, solar energy here swings from a low near 2.85 kWh/m² to a high of 5.08 kWh/m² in April across the year — September's 4.38 kWh/m² falls in the middle.

012345151015202530
Solar energy (kWh/m²)Level
14.4Bright
24.4Bright
34.4Bright
44.4Bright
54.4Bright
64.4Bright
74.4Bright
84.4Bright
94.4Bright
104.4Bright
114.4Bright
124.4Bright
134.4Bright
144.4Bright
154.4Bright
164.4Bright
174.4Bright
184.4Bright
194.4Bright
204.4Bright
214.3Bright
224.3Bright
234.3Bright
244.3Bright
254.3Bright
264.3Bright
274.3Bright
284.3Bright
294.3Bright
304.2Bright
Planning a trip in September

Hazard calendar for Sapa

In seasonPeak

In September, Sapa sits inside its monsoon season. The full year is below, with each hazard's peak months called out.

Sapa's monsoon runs May–September, when most of the year's rain falls.

Monsoon
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Sapa?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

4.5
Sightseeing
8th-best month of the year
4.5
Beach & pool
3rd-best month of the year

September is a reasonable time to visit Sapa for sightseeing.

What to pack for Sapa in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Sapa sees daytime highs around 26°C and nights near 20°C. Pack rain gear. Worth having: light clothes. About 22 days see rain.

rain gearlight clothes

UV index in Sapa in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Sapa peaks around June 21 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 18 at about 5 (high).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecHighVery highVery highExtremeVery highHighJun 21UV 13Dec 18UV 5
UV index (midday)Level
Jan6High
Feb8Very high
Mar11Extreme
Apr8Very high
May10Very high
Jun14Extreme
Jul13Extreme
Aug12Extreme
Sep10Very high
Oct8Very high
Nov7High
Dec5High

Air quality in Sapa in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual average.

Air quality in Sapa is worst in April — around 70 µg/m³ PM2.5 (unhealthy), about 5.0× the cleanest month (July, 14 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

020406080JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyModerateApr 1367 µg/m³Jul 1814 µg/m³
PM2.5 (µg/m³)Level
Jan25Moderate
Feb33Moderate
Mar54Poor
Apr70Unhealthy
May28Moderate
Jun15Moderate
Jul14Moderate
Aug15Moderate
Sep18Moderate
Oct22Moderate
Nov23Moderate
Dec25Moderate
Location & terrain

Where is Sapa?

Sapa sits at 22.3°N, 103.8°E, 0 m above sea level, in Vietnam. The nearest listed city is Lào Cai, 21 km away.

Ít OngThị Trấn Việt QuangThị Trấn Thuận ChâuBắc Quang

Topography around Sapa

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Sapa.

Within 3 km, the terrain around Sapa has large variations in elevation — a maximum elevation change of 957 m around an average of 1,481 m above sea level; within 16 km, extreme variations in elevation — a maximum elevation change of 3,006 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,050 m.

The land around Sapa is covered by trees (56%) and grassland (28%) within 3 km, trees (86%) within 16 km, and trees (84%) within 80 km.

3 km
957 m
16 km
3,006 m
80 km
3,050 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Lào Cai 21 km · Thị Trấn Phố Lu 35 km · Lai Châu 40 km · Mường Lay 82 km · Ít Ong 93 km · Thị Trấn Việt Quang 99 km · Thị Trấn Thuận Châu 102 km · Bắc Quang 106 km

Vietnam travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B / C / F
220 V · 50 Hz
Prices
≈ 29% of US
price level, 2025
GDP per capita
$5,066
2025
Happiness
6.4 / 10
World Happiness, 2025
Safe drinking water
59%
of population, 2024
Homicide rate
1.5
per 100k, 2011
Road deaths
30.6
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Moderate
EF EPI 500
Religion
none 86%Catholic 6%Buddhist 6%Protestant 1%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Sapa (22.3402°, 103.8441°, elevation 0 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).