Lào Cai weather in September

In September, Lào Cai sees average daytime highs of 28°C and overnight lows near 22°C, with 165 mm of rain across 18.2 wet days and about 12.1 hours of daylight. It is the 5th-warmest and 5th-wettest month of the year here.

Highs ease over the month, from about 29°C in the first days to 27°C by the end. The sky is clear or mostly clear about 20% of the time in September, and the air most often feels oppressive.

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 Lào Cai's 7th-clearest and 9th-windiest month. For the whole year in context, see Lào Cai's year-round climate.

Daytime high
28°
5th warmest
Overnight low
22°
9th coldest
Rainfall
165 mm
18.2 wet days
Daylight
12 h 06 min
5:55 AM – 6:02 PM
Cloud cover
68%
7th clearest
Wind
3 km/h
9th windiest
Solar energy
4.27 kWh/m²
Travel score
4.6
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 29°C in the first days to 27°C by the end.

A typical September day in Lào Cai reaches about 28°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 25°C and 31°C. Set against its neighbours, September runs about 1°C cooler than August and about 3°C warmer than October.

15°20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
12923
22923
32923
42923
52923
62922
72922
82922
92922
102922
112922
122922
132922
142922
152922
162822
172822
182822
192822
202822
212821
222821
232821
242821
252821
262821
272821
282821
292721
302721

How September really feels in Lào Cai

Once humidity and wind are folded in, September averages 3 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
3
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.

Lào Cai 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° / 11°9618.110.84.7
Feb20° / 12°871711.25.0
Mar24° / 15°1261911.85.5
Apr27° / 19°12917.612.55.2
May29° / 22°20019.713.14.1
Jun30° / 24°2422213.43.3
Jul30° / 24°26123.213.23.4
Aug30° / 23°26822.412.83.6
Sep28° / 22°16518.212.14.6
Oct26° / 19°11816.611.55.7
Nov23° / 15°8813.810.96.1
Dec19° / 12°9214.110.65.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% 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 65%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12872
22872
32872
42971
52971
63070
73070
83070
93169
103169
113169
123268
133268
143367
153565
163565
173664
183664
193763
203763
213961
224060
234159
244258
254258
264357
274357
284357
294456
304456

Chance of precipitation in September

Any precipitation

Lào Cai gets around 165 mm of rain over 18.2 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 61% and peaks near 68% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
168
268
367
467
566
666
765
865
964
1064
1163
1263
1363
1462
1562
1661
1761
1860
1959
2059
2158
2258
2357
2456
2555
2655
2754
2853
2952
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 58% of days. Sticky, muggy-or-worse air turns up on roughly 92% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10117811
20118810
30219790
40221770
50222760
60223750
71324720
81325710
91326700
101328680
111429660
121430650
131431640
142432620
152533600
162535580
172636560
182637550
193738520
203739510
213840490
223941480
233942450
2431043430
2541144410
2641246390
2741347370
2841347350
2951448330
3051549310

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 4 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
284calm
294calm
304calm

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 5:50 AM to 5:59 AM, and sunset from 6:17 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.55:506:17
212.45:506:17
312.45:516:16
412.45:516:15
512.45:516:14
612.35:526:13
712.35:526:12
812.35:526:11
912.35:536:10
1012.35:536:08
1112.25:536:07
1212.25:536:06
1312.25:546:05
1412.25:546:04
1512.25:546:03
1612.15:556:02
1712.15:556:01
1812.15:556:00
1912.15:555:59
2012.05:565:58
2112.05:565:57
2212.05:565:56
2312.05:575:55
2411.95:575:54
2511.95:575:53
2611.95:585:52
2711.95:585:51
2811.95:585:50
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 4.27 kWh/m².

For context, solar energy here swings from a low near 2.56 kWh/m² to a high of 4.91 kWh/m² in April across the year — September's 4.27 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
104.3Bright
114.3Bright
124.3Bright
134.3Bright
144.3Bright
154.3Bright
164.3Bright
174.2Bright
184.2Bright
194.2Bright
204.2Bright
214.2Bright
224.2Bright
234.1Bright
244.1Bright
254.1Bright
264.1Bright
274.1Bright
284.0Bright
294.0Bright
304.0Moderate
Planning a trip in September

Hazard calendar for Lào Cai

In seasonPeak

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

Lào Cai's rainy season runs March–September, when most of the year's rain falls.

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

Is September a good time to visit Lào Cai?

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

4.6
Sightseeing
8th-best month of the year
5.4
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Lào Cai for sightseeing.

What to pack for Lào Cai in September

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

In September, Lào Cai sees daytime highs around 28°C and nights near 22°C. Pack light clothes and rain gear. About 18 days see rain.

light clothesrain gear

UV index in Lào Cai 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 Lào Cai 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 Lào Cai 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 Lào Cai is worst in March — around 49 µg/m³ PM2.5 (poor), about 2.8× the cleanest month (July, 17 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecPoorModeratePoorMar 2349 µg/m³Jul 1817 µg/m³
PM2.5 (µg/m³)Level
Jan36Poor
Feb40Poor
Mar49Poor
Apr48Poor
May30Moderate
Jun19Moderate
Jul17Moderate
Aug18Moderate
Sep23Moderate
Oct28Moderate
Nov33Moderate
Dec36Poor
Location & terrain

Where is Lào Cai?

Lào Cai sits at 22.5°N, 104.0°E, 86 m above sea level, in Vietnam. The nearest listed city is Sapa, 21 km away.

Bắc QuangMường LayÍt OngHà Giang

Topography around Lào Cai

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

Within 3 km, the terrain around Lào Cai has significant variations in elevation — a maximum elevation change of 298 m around an average of 141 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 2,148 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,050 m.

The land around Lào Cai is covered by trees (65%) and artificial surfaces (26%) within 3 km, trees (90%) within 16 km, and trees (85%) within 80 km.

3 km
298 m
16 km
2,148 m
80 km
3,050 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Sapa 21 km · Thị Trấn Phố Lu 29 km · Lai Châu 54 km · Thị Trấn Việt Quang 86 km · Bắc Quang 92 km · Mường Lay 102 km · Ít Ong 108 km · Hà Giang 111 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 Lào Cai (22.4856°, 103.9707°, elevation 86 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).