Móng Cái weather in September

In September, Móng Cái sees average daytime highs of 29°C and overnight lows near 26°C, with 253 mm of rain across 18.6 wet days and about 12.1 hours of daylight. It is the 4th-warmest and 4th-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 33% of the time in September, and the air most often feels miserable.

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 Móng Cái's 4th-clearest and 11th-windiest month. For the whole year in context, see Móng Cái's year-round climate.

Daytime high
29°
4th warmest
Overnight low
26°
9th coldest
Rainfall
253 mm
18.6 wet days
Daylight
12 h 06 min
5:39 AM – 5:46 PM
Cloud cover
61%
4th clearest
Wind
12 km/h
11th windiest
Solar energy
4.81 kWh/m²
Travel score
4.3
out of 10

Móng Cái is provincial city of Vietnam.

Density
211/km²
people per km²

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 Móng Cái reaches about 29°C in the afternoon and slips back to 26°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 31°C. Set against its neighbours, September runs on par with August and about 2°C warmer than October.

20°25°30°35°151015202530
Avg high (°C)Avg low (°C)
13027
23027
33027
43027
53027
63027
73027
83027
93026
103026
113026
122926
132926
142926
152926
162926
172926
182926
192926
202926
212926
222926
232926
242926
252926
262926
272925
282925
292925
302925

How September really feels in Móng Cái

Once humidity and wind are folded in, September averages 29 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
29
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.

Móng Cái weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan17° / 14°6912.710.85.0
Feb18° / 15°501111.35.4
Mar21° / 18°7413.111.85.7
Apr24° / 22°7112.712.56.2
May28° / 25°20919134.8
Jun30° / 27°28823.513.33.4
Jul30° / 27°3802513.23.2
Aug30° / 27°37424.612.73.3
Sep29° / 26°25318.612.14.3
Oct27° / 24°9910.311.56.7
Nov23° / 20°679.1117.1
Dec19° / 16°538.810.76.3

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 13% of September, with mostly cloudy or overcast conditions the remaining 54%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13565
23565
33466
43466
53565
63565
73664
83664
93862
103961
113961
124159
134258
144357
154555
164753
174852
184852
195050
205149
215248
225347
235446
245545
255743
265842
275842
285941
296040
306139

Chance of precipitation in September

Any precipitation

Móng Cái gets around 253 mm of rain over 18.6 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 62% and peaks near 75% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
175
275
374
474
574
673
773
872
971
1070
1169
1267
1366
1465
1563
1662
1760
1859
1958
2056
2155
2253
2352
2451
2550
2649
2748
2847
2946
3045

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the miserable band about 64% of days. Sticky, muggy-or-worse air turns up on roughly 98% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10011188
20011287
30011287
40111385
50121384
60121483
70131482
80131581
90141679
100141679
110251776
120261874
130271972
140272071
150282268
160292366
1702102563
1802112661
1902122858
2002123056
2102133154
2202143351
2302143549
2403153646
2503153744
2603163842
2704173940
2814184038
2915184136
3016194134

Wind in September

Winds average 12 km/h in September.

Across September, daily wind ranges from about 11 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
111calm
211calm
311calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1412calm
1512calm
1612calm
1712calm
1812light breeze
1912light breeze
2012light breeze
2112light breeze
2212light breeze
2312light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

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 5:35 AM to 5:43 AM, and sunset from 6:01 PM to 5:32 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:356:01
212.45:356:00
312.45:355:59
412.45:365:58
512.45:365:57
612.35:365:56
712.35:365:55
812.35:375:54
912.35:375:53
1012.25:375:52
1112.25:375:51
1212.25:385:50
1312.25:385:49
1412.25:385:48
1512.15:395:47
1612.15:395:46
1712.15:395:45
1812.15:395:44
1912.15:405:43
2012.05:405:42
2112.05:405:41
2212.05:405:40
2312.05:415:39
2412.05:415:38
2511.95:415:37
2611.95:425:36
2711.95:425:35
2811.95:425:34
2911.85:425:33
3011.85:435:32

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.81 kWh/m².

For context, solar energy here swings from a low near 2.69 kWh/m² to a high of 5.1 kWh/m² in May across the year — September's 4.81 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.8Bright
34.8Bright
44.8Bright
54.8Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.8Bright
164.8Bright
174.9Bright
184.9Bright
194.9Bright
204.9Bright
214.9Bright
224.9Bright
234.9Bright
244.9Bright
254.9Bright
264.9Bright
274.9Bright
284.9Bright
294.9Bright
304.9Bright
Planning a trip in September

Hazard calendar for Móng Cái

In seasonPeak

In September, Móng Cái sits inside its pacific typhoon and monsoon season. The full year is below, with each hazard's peak months called out.

Móng Cái sits in the Pacific typhoon belt; the season peaks July–October.

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

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

Is September a good time to visit Móng Cái?

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

4.3
Sightseeing
9th-best month of the year
5.6
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Móng Cái for sightseeing.

What to pack for Móng Cái in September

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

In September, Móng Cái sees daytime highs around 29°C and nights near 26°C. Pack light clothes and rain gear. Worth having: sun protection. About 19 days see rain.

light clothesrain gearsun protection

Sea temperature near Móng Cái in September

The nearest coast averages about 29°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 19 km away) is warmest in August at about 30°C and coldest in February near 19°C.

It's comfortable for a long swim from Mar 15 to Dec 30 — about 9.6 months when the water holds above 20°C.

20°25°30°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan19Cool
Feb19Cool
Mar20Refreshing
Apr23Refreshing
May27Warm
Jun29Tropical
Jul29Tropical
Aug30Tropical
Sep29Tropical
Oct27Warm
Nov24Warm
Dec21Refreshing

UV index in Móng Cái in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 9 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Móng Cái peaks around July 9 at about 12 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 6 (high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecHighVery highExtremeVery highHighJul 9UV 12Dec 17UV 6
UV index (midday)Level
Jan6High
Feb8Very high
Mar9Very high
Apr8Very high
May10Very high
Jun12Extreme
Jul12Extreme
Aug8Very high
Sep9Very high
Oct9Very high
Nov7High
Dec6High

Air quality in Móng Cái 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 Móng Cái is worst in December — around 46 µg/m³ PM2.5 (poor), about 2.8× the cleanest month (July, 16 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecPoorModeratePoorDec 2346 µg/m³Jul 1416 µg/m³
PM2.5 (µg/m³)Level
Jan45Poor
Feb42Poor
Mar44Poor
Apr38Poor
May25Moderate
Jun17Moderate
Jul16Moderate
Aug18Moderate
Sep25Moderate
Oct32Moderate
Nov35Moderate
Dec46Poor
Location & terrain

Where is Móng Cái?

Móng Cái sits at 21.5°N, 108.0°E, 9 m above sea level, in Vietnam. The nearest listed city is Thị Trấn Đầm Hà, 43 km away.

Cẩm PhảThị Trấn Na DươngHa LongLạng Sơn

Topography around Móng Cái

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

Within 3 km, the terrain around Móng Cái has only modest variations in elevation — a maximum elevation change of 43 m around an average of 8 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 367 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,472 m.

The land around Móng Cái is covered by artificial surfaces (38%) and trees (24%) within 3 km, water (44%) and trees (38%) within 16 km, and trees (53%) and water (40%) within 80 km.

3 km
43 m
16 km
367 m
80 km
1,472 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Thị Trấn Đầm Hà 43 km · Thị Trấn Tiên Yên 62 km · Thị Trấn Ba Chẽ 76 km · Cẩm Phả Mines 89 km · Cẩm Phả 92 km · Thị Trấn Na Dương 106 km · Ha Long 112 km · Lạng Sơn 130 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 Móng Cái (21.5247°, 107.9662°, elevation 9 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).