Mường Lay weather in September

In September, Mường Lay sees average daytime highs of 29°C and overnight lows near 22°C, with 187 mm of rain across 19.7 wet days and about 12.1 hours of daylight. It is the 4th-warmest and 6th-wettest month of the year here.

Day-to-day highs hold fairly steady near 29°C through the month. The sky is clear or mostly clear about 18% of the time in September, and the air most often feels oppressive.

Daylight stretches from about 12 h 24 min at the start of September to 11 h 48 min by month's end. Set against the rest of the year, September is Mường Lay's 8th-clearest and 9th-windiest month. For the whole year in context, see Mường Lay's year-round climate.

Daytime high
29°
4th warmest
Overnight low
22°
9th coldest
Rainfall
187 mm
19.7 wet days
Daylight
12 h 06 min
5:58 AM – 6:06 PM
Cloud cover
70%
8th clearest
Wind
2 km/h
9th windiest
Solar energy
4.44 kWh/m²
Travel score
4.2
out of 10

Mường Lay is old town of Dien Bien province, Vietnam.

Density
179/km²
people per km²
Founded
1971

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 29°C through the month.

A typical September day in Mường Lay reaches about 29°C in the afternoon and slips back to 22°C overnight — a 7°C spread between the day's warmth and the night's chill. On most days the high lands between 26°C and 31°C. Set against its neighbours, September runs on par with August and about 2°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12922
22922
32922
42922
52922
62922
72922
82922
92922
102922
112922
122922
132922
142922
152922
162922
172922
182922
192922
202922
212922
222921
232921
242921
252921
262821
272821
282821
292821
302821

How September really feels in Mường Lay

Once humidity and wind are folded in, September averages 7 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
7
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Mường Lay weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan21° / 12°59810.86.8
Feb23° / 12°548.311.27.1
Mar26° / 15°12313.111.86.3
Apr28° / 19°21919.512.54.7
May29° / 21°32825.2133.5
Jun29° / 23°45528.313.32.9
Jul29° / 23°45329.413.23.0
Aug29° / 23°36426.912.83.2
Sep29° / 22°18719.712.14.2
Oct27° / 20°8613.711.55.9
Nov24° / 16°55810.97.2
Dec21° / 13°476.210.77.1

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 18% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 16% of September, with mostly cloudy or overcast conditions the remaining 66%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12575
22575
32575
42674
52575
62674
72674
82674
92773
102773
112872
122971
133070
143070
153169
163268
173367
183466
193466
203763
213862
223961
234060
244258
254357
264456
274555
284555
294654
304852

Chance of precipitation in September

Any precipitation

Mường Lay gets around 187 mm of rain over 19.7 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 66% and peaks near 78% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
178
278
377
476
575
674
774
873
972
1071
1170
1269
1369
1468
1567
1666
1765
1864
1963
2062
2161
2260
2359
2458
2557
2655
2754
2853
2953
3052

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the oppressive band about 76% of days. Sticky, muggy-or-worse air turns up on roughly 96% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1005941
2006931
3007921
4008911
5019891
60110881
70111880
80112870
90113860
100114850
110215830
120216820
130217810
140218800
150318790
160319780
170320770
180421750
190423730
200424720
210525700
220527680
230529660
240630640
250632620
261734580
271736560
281838530
291840510
301842490

Wind in September

Winds average 2 km/h in September.

Across September, daily wind ranges from about 2 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
12calm
22calm
32calm
42calm
52calm
62calm
72calm
82calm
92calm
102calm
112calm
122calm
132calm
142calm
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 24 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 36 minutes over September. Sunrise moves from 5:54 AM to 6:02 AM, and sunset from 6:21 PM to 5:51 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:546:21
212.45:546:20
312.45:546:19
412.45:556:18
512.45:556:17
612.35:556:16
712.35:566:15
812.35:566:14
912.35:566:13
1012.35:566:12
1112.25:576:11
1212.25:576:10
1312.25:576:09
1412.25:576:08
1512.15:586:07
1612.15:586:06
1712.15:586:05
1812.15:596:03
1912.15:596:02
2012.05:596:01
2112.05:596:00
2212.06:005:59
2312.06:005:58
2412.06:005:57
2511.96:015:56
2611.96:015:55
2711.96:015:54
2811.96:025:53
2911.86:025:52
3011.86:025:51

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.44 kWh/m².

For context, solar energy here swings from a low near 3.09 kWh/m² to a high of 5.2 kWh/m² in April across the year — September's 4.44 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
114.5Bright
124.5Bright
134.5Bright
144.5Bright
154.5Bright
164.5Bright
174.5Bright
184.5Bright
194.5Bright
204.4Bright
214.4Bright
224.4Bright
234.4Bright
244.4Bright
254.4Bright
264.4Bright
274.4Bright
284.4Bright
294.4Bright
304.4Bright
Planning a trip in September

Hazard calendar for Mường Lay

In seasonPeak

None of Mường Lay's seasonal hazards are active in September. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Mường Lay's monsoon runs April–August, 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 Mường Lay?

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

4.2
Sightseeing
8th-best month of the year
5.2
Beach & pool
6th-best month of the year

September is a reasonable time to visit Mường Lay for sightseeing.

What to pack for Mường Lay in September

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

In September, Mường Lay sees daytime highs around 29°C and nights near 22°C. Pack light clothes and rain gear. About 20 days see rain.

light clothesrain gear

UV index in Mường Lay 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 Mường Lay peaks around June 19 at about 13 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 6 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecVery highVery highExtremeVery highHighJun 19UV 13Dec 19UV 6
UV index (midday)Level
Jan7High
Feb9Very high
Mar11Extreme
Apr9Very high
May11Extreme
Jun14Extreme
Jul13Extreme
Aug12Extreme
Sep10Very high
Oct9Very high
Nov8Very high
Dec6High

Air quality in Mường Lay 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 Mường Lay is worst in April — around 99 µg/m³ PM2.5 (unhealthy), about 8.1× the cleanest month (July, 12 µg/m³).

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

0306090120JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorUnhealthyModerateApr 1395 µg/m³Jul 2212 µg/m³
PM2.5 (µg/m³)Level
Jan31Moderate
Feb41Poor
Mar73Unhealthy
Apr99Unhealthy
May32Moderate
Jun14Moderate
Jul12Moderate
Aug13Moderate
Sep17Moderate
Oct23Moderate
Nov26Moderate
Dec30Moderate
Location & terrain

Where is Mường Lay?

Mường Lay sits at 22.0°N, 103.1°E, 496 m above sea level, in Vietnam. The nearest listed city is Lai Châu, 55 km away.

Lào CaiÍt OngSơn LaThị Trấn Phố Lu

Topography around Mường Lay

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

Within 3 km, the terrain around Mường Lay has large variations in elevation — a maximum elevation change of 987 m around an average of 501 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,867 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,950 m.

The land around Mường Lay is covered by trees (78%) within 3 km, trees (80%) within 16 km, and trees (80%) within 80 km.

3 km
987 m
16 km
1,867 m
80 km
2,950 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Lai Châu 55 km · Dien Bien Phu 69 km · Sapa 82 km · Thị Trấn Thuận Châu 85 km · Lào Cai 102 km · Ít Ong 107 km · Sơn La 111 km · Thị Trấn Phố Lu 114 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 Mường Lay (22°, 103.1333°, elevation 496 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).