Cát Bà weather in August

In August, Cát Bà sees average daytime highs of 30°C and overnight lows near 27°C, with 399 mm of rain across 24 wet days and about 12.7 hours of daylight. It is the 3rd-warmest and 1st-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 14% of the time in August, and the air most often feels miserable.

Daylight stretches from about 13 hours at the start of August to 12 h 24 min by month's end. Set against the rest of the year, August is Cát Bà's 10th-clearest and 11th-windiest month. For the whole year in context, see Cát Bà's year-round climate.

Daytime high
30°
3rd warmest
Overnight low
27°
10th coldest
Rainfall
399 mm
24 wet days
Daylight
12 h 42 min
5:34 AM – 6:17 PM
Cloud cover
79%
10th clearest
Wind
14 km/h
11th windiest
Solar energy
4.78 kWh/m²
Travel score
3.3
out of 10

Cát Bà is town in Vietnam.

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

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

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

A typical August day in Cát Bà reaches about 30°C in the afternoon and slips back to 27°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 28°C and 32°C. Set against its neighbours, August runs on par with July and on par with September.

25°28°30°33°35°151015202531
Avg high (°C)Avg low (°C)
13028
23028
33028
43028
53028
63028
73028
83028
93028
103028
113028
123027
133027
143027
153027
163027
173027
183027
193027
203027
213027
223027
233027
243027
253027
263027
273027
283027
293027
303027
313027

How August really feels in Cát Bà

Once humidity and wind are folded in, August averages 31 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
31
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

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

Cát Bà weather by month

How August compares with the rest of the year at a glance. August is the 3rd-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan19° / 16°407.610.96.2
Feb19° / 17°235.711.36.4
Mar21° / 19°407.611.96.6
Apr25° / 23°527.712.57.0
May28° / 26°18515.5135.1
Jun30° / 28°21517.813.23.7
Jul30° / 28°30319.813.13.6
Aug30° / 27°3992412.73.3
Sep29° / 26°3052012.14.0
Oct28° / 25°13411.611.56.2
Nov24° / 21°568.4117.2
Dec21° / 18°396.310.86.9

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

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

Beyond those clear spells, partly cloudy skies cover about 9% of August, with mostly cloudy or overcast conditions the remaining 77%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
12377
22377
32278
42278
52278
62080
72080
81981
91981
101981
111981
121981
132080
142179
152179
162179
172179
182377
192377
202377
212476
222575
232674
242674
252872
262872
272872
282971
292971
302971
312872

Chance of precipitation in August

Any precipitation

Cát Bà gets around 399 mm of rain over 24 wet days in August, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 77% and peaks near 81% on the wettest days. The odds climb toward the end of the month.

0%20%40%60%80%151015202531
Rain chance (%)
174
274
374
474
574
674
774
875
975
1075
1176
1276
1376
1477
1577
1677
1777
1878
1978
2078
2179
2279
2379
2479
2580
2680
2780
2880
2981
3081
3181

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the miserable band about 98% of days. Sticky, muggy-or-worse air turns up on roughly 100% of them.

0%25%50%75%100%151015202531
Oppressive (%)Miserable (%)
10100
20100
30100
40100
50100
60100
70100
80100
90100
10199
11199
12199
13199
14199
15298
16298
17298
18298
19397
20397
21397
22397
23397
24496
25496
26496
27595
28595
29595
30694
31694

Wind in August

Winds average 14 km/h in August.

Across August, daily wind ranges from about 12 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze
3112light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 hours at the start of August to 12 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 36 minutes over August. Sunrise moves from 5:29 AM to 5:39 AM, and sunset from 6:26 PM to 6:05 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:296:26
212.95:306:26
312.95:306:25
412.95:306:25
512.95:316:24
612.95:316:24
712.95:316:23
812.85:326:23
912.85:326:22
1012.85:326:21
1112.85:336:21
1212.85:336:20
1312.85:336:19
1412.75:346:19
1512.75:346:18
1612.75:346:17
1712.75:356:17
1812.75:356:16
1912.75:356:15
2012.65:366:14
2112.65:366:13
2212.65:366:13
2312.65:376:12
2412.65:376:11
2512.65:376:10
2612.55:376:09
2712.55:386:08
2812.55:386:08
2912.55:386:07
3012.55:396:06
3112.45:396:05

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 4.78 kWh/m².

For context, solar energy here swings from a low near 2.74 kWh/m² to a high of 5.4 kWh/m² in May across the year — August's 4.78 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.9Bright
24.9Bright
34.9Bright
44.9Bright
54.9Bright
64.8Bright
74.8Bright
84.8Bright
94.8Bright
104.8Bright
114.8Bright
124.8Bright
134.8Bright
144.8Bright
154.7Bright
164.7Bright
174.7Bright
184.7Bright
194.7Bright
204.7Bright
214.7Bright
224.7Bright
234.7Bright
244.7Bright
254.7Bright
264.7Bright
274.7Bright
284.7Bright
294.7Bright
304.7Bright
314.6Bright
Planning a trip in August

Hazard calendar for Cát Bà

In seasonPeak

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

Cát Bà sits in the Pacific typhoon belt; the season peaks July–October.

Cát Bà'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 August a good time to visit Cát Bà?

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

3.3
Sightseeing
12th-best month of the year
4.6
Beach & pool
8th-best month of the year

August is a weaker month for outdoor sightseeing in Cát Bà.

What to pack for Cát Bà in August

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

In August, Cát Bà sees daytime highs around 30°C and nights near 27°C. Pack light clothes and rain gear. Worth having: sun protection. About 24 days see rain.

light clothesrain gearsun protection

Sea temperature near Cát Bà in August

The nearest coast averages about 30°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 14 km away) is warmest in August at about 30°C and coldest in February near 20°C.

It's comfortable for a long swim from Mar 6 to Jan 18 — about 10.5 months when the water holds above 20°C.

20°25°30°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°C)Comfort
Jan20Refreshing
Feb20Cool
Mar20Refreshing
Apr23Refreshing
May27Warm
Jun29Tropical
Jul30Tropical
Aug30Tropical
Sep29Tropical
Oct28Warm
Nov25Warm
Dec22Refreshing

UV index in Cát Bà in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August 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 Cát Bà peaks around July 12 at about 12 (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 highExtremeVery highHighJul 12UV 12Dec 19UV 6
UV index (midday)Level
Jan7High
Feb8Very high
Mar9Very high
Apr8Very high
May10Extreme
Jun12Extreme
Jul12Extreme
Aug9Very high
Sep9Very high
Oct9Very high
Nov7High
Dec6High

Air quality in Cát Bà in August

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Cát Bà 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 Cát Bà?

Cát Bà sits at 20.7°N, 107.0°E, 24 m above sea level, in Vietnam. The nearest listed city is Ha Long, 25 km away.

Topography around Cát Bà

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

Within 3 km, the terrain around Cát Bà has only modest variations in elevation — a maximum elevation change of 205 m around an average of 22 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 299 m; within 80 km, large variations in elevation — a maximum elevation change of 1,180 m.

The land around Cát Bà is covered by water (58%) and trees (36%) within 3 km, water (80%) within 16 km, and water (51%) and trees (29%) within 80 km.

3 km
205 m
16 km
299 m
80 km
1,180 m
treesgrasslandcroplandartificial surfacesbare terrainwatermangroves
August weather nearby: Ha Long 25 km · Đố Sơn 27 km · Cẩm Phả 39 km · Haiphong 41 km · Cẩm Phả Mines 41 km · Thành Phố Uông Bí 45 km · Kiến An 45 km · Thị Trấn Mạo Khê 60 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 Cát Bà (20.7278°, 107.0482°, elevation 24 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).