Thị Trấn Ba Chẽ weather in September

In September, Thị Trấn Ba Chẽ sees average daytime highs of 30°C and overnight lows near 24°C, with 227 mm of rain across 19.5 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 30°C through the month. The sky is clear or mostly clear about 23% 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 Thị Trấn Ba Chẽ's 4th-clearest and 11th-windiest month. For the whole year in context, see Thị Trấn Ba Chẽ's year-round climate.

Daytime high
30°
4th warmest
Overnight low
24°
9th coldest
Rainfall
227 mm
19.5 wet days
Daylight
12 h 06 min
5:42 AM – 5:49 PM
Cloud cover
68%
4th clearest
Wind
7 km/h
11th windiest
Solar energy
4.51 kWh/m²
Travel score
3.7
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 30°C through the month.

A typical September day in Thị Trấn Ba Chẽ reaches about 30°C in the afternoon and slips back to 24°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 27°C and 33°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)
13125
23125
33125
43025
53025
63025
73025
83025
93025
103024
113024
123024
133024
143024
153024
163024
173024
183024
193024
203024
213024
223024
233024
243024
253024
263023
273023
283023
293023
303023

How September really feels in Thị Trấn Ba Chẽ

Once humidity and wind are folded in, September averages 30 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
30
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.

Thị Trấn Ba Chẽ 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
Jan18° / 13°346.310.86.2
Feb20° / 15°215.411.36.4
Mar22° / 17°458.211.86.5
Apr26° / 21°6411.512.56.0
May29° / 24°20819.7134.0
Jun31° / 26°2982413.32.8
Jul31° / 26°33825.613.22.8
Aug31° / 25°37426.312.72.8
Sep30° / 24°22719.512.13.7
Oct28° / 22°8710.411.56.0
Nov25° / 18°497.9117.2
Dec21° / 14°336.310.76.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 23% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 63%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12773
22773
32773
42773
52872
62872
72773
82872
92971
102971
113169
123367
133367
143565
153565
163763
173862
184060
194159
204258
214456
224555
234654
244852
254852
264852
275050
285050
295248
305347

Chance of precipitation in September

Any precipitation

Thị Trấn Ba Chẽ gets around 227 mm of rain over 19.5 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 65% and peaks near 82% on the wettest days. The odds ease toward the end of the month.

0%20%40%60%80%151015202530
Rain chance (%)
182
282
381
481
580
679
778
877
975
1074
1173
1271
1370
1468
1566
1664
1763
1861
1959
2058
2156
2255
2354
2452
2551
2650
2749
2848
2947
3046

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 53% of days. Sticky, muggy-or-worse air turns up on roughly 97% of them.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
10012079
20012178
30012277
40112474
50122572
60122671
70132670
80132769
90242866
100252865
110262963
120263062
130273061
140283159
1503103255
1603113254
1703123352
1803133450
1913143547
2013153645
2113163743
2213173841
2314183938
2414194136
2514194233
2615204331
2716214429
2816214526
2917224524
3028224623

Wind in September

Winds average 7 km/h in September.

Across September, daily wind ranges from about 6 km/h on the calmest days to 8 km/h at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (km/h)Feels
16calm
26calm
36calm
46calm
56calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
207calm
217calm
228calm
238calm
248calm
258calm
268calm
278calm
288calm
298calm
308calm

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 5:38 AM to 5:45 AM, and sunset from 6:03 PM to 5:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.45:386:03
212.45:386:02
312.45:386:02
412.45:396:01
512.35:396:00
612.35:395:59
712.35:395:58
812.35:405:57
912.35:405:56
1012.25:405:55
1112.25:405:54
1212.25:415:53
1312.25:415:52
1412.25:415:51
1512.15:415:50
1612.15:425:49
1712.15:425:48
1812.15:425:47
1912.15:425:46
2012.05:435:45
2112.05:435:44
2212.05:435:43
2312.05:435:42
2412.05:445:41
2511.95:445:40
2611.95:445:39
2711.95:445:38
2811.95:455:37
2911.85:455:36
3011.85:455:35

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.51 kWh/m².

For context, solar energy here swings from a low near 2.53 kWh/m² to a high of 4.77 kWh/m² in May across the year — September's 4.51 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.4Bright
54.4Bright
64.4Bright
74.4Bright
84.4Bright
94.5Bright
104.5Bright
114.5Bright
124.5Bright
134.5Bright
144.5Bright
154.5Bright
164.5Bright
174.6Bright
184.6Bright
194.6Bright
204.6Bright
214.6Bright
224.6Bright
234.6Bright
244.6Bright
254.6Bright
264.6Bright
274.6Bright
284.6Bright
294.6Bright
304.6Bright
Planning a trip in September

Hazard calendar for Thị Trấn Ba Chẽ

In seasonPeak

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

Thị Trấn Ba Chẽ sits in the Pacific typhoon belt; the season peaks July–October.

Thị Trấn Ba Chẽ'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 Thị Trấn Ba Chẽ?

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

3.7
Sightseeing
9th-best month of the year
5.2
Beach & pool
4th-best month of the year

September is a weaker month for outdoor sightseeing in Thị Trấn Ba Chẽ.

What to pack for Thị Trấn Ba Chẽ in September

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

In September, Thị Trấn Ba Chẽ sees daytime highs around 30°C and nights near 24°C. Pack light clothes and rain gear. Worth having: sun protection. About 20 days see rain.

light clothesrain gearsun protection

Sea temperature near Thị Trấn Ba Chẽ 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 39 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 Jan 4 — about 9.7 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
Oct28Warm
Nov25Warm
Dec21Refreshing

UV index in Thị Trấn Ba Chẽ 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 Thị Trấn Ba Chẽ peaks around July 11 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 11UV 12Dec 17UV 6
UV index (midday)Level
Jan7High
Feb8Very high
Mar9Very high
Apr8Very high
May10Extreme
Jun12Extreme
Jul13Extreme
Aug8Very high
Sep9Very high
Oct9Very high
Nov7High
Dec6High

Air quality in Thị Trấn Ba Chẽ 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 Thị Trấn Ba Chẽ is worst in January — around 42 µg/m³ PM2.5 (poor), about 2.6× the cleanest month (July, 16 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecPoorModeratePoorJan 2342 µg/m³Jul 1716 µg/m³
PM2.5 (µg/m³)Level
Jan42Poor
Feb42Poor
Mar41Poor
Apr40Poor
May26Moderate
Jun19Moderate
Jul16Moderate
Aug18Moderate
Sep21Moderate
Oct27Moderate
Nov29Moderate
Dec39Poor
Location & terrain

Where is Thị Trấn Ba Chẽ?

Thị Trấn Ba Chẽ sits at 21.3°N, 107.3°E, 16 m above sea level, in Vietnam. The nearest listed city is Thị Trấn Tiên Yên, 14 km away.

Topography around Thị Trấn Ba Chẽ

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Thị Trấn Ba Chẽ.

Within 3 km, the terrain around Thị Trấn Ba Chẽ has significant variations in elevation — a maximum elevation change of 422 m around an average of 94 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 885 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,603 m.

The land around Thị Trấn Ba Chẽ is covered by trees (88%) within 3 km, trees (82%) within 16 km, and trees (57%) and water (35%) within 80 km.

3 km
422 m
16 km
885 m
80 km
1,603 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
September weather nearby: Thị Trấn Tiên Yên 14 km · Cẩm Phả Mines 28 km · Cẩm Phả 29 km · Thị Trấn Đầm Hà 34 km · Ha Long 42 km · Thị Trấn Na Dương 59 km · Thành Phố Uông Bí 59 km · Cát Bà 65 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 Thị Trấn Ba Chẽ (21.2716°, 107.2836°, elevation 16 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).