Cát Bà weather in January

In January, Cát Bà sees average daytime highs of 19°C and overnight lows near 16°C, with 40 mm of rain across 7.6 wet days and about 10.9 hours of daylight. It is the 12th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 19°C through the month. The sky is clear or mostly clear about 20% of the time in January, and the air most often feels dry.

Daylight stretches from about 10 h 48 min at the start of January to 11 h 06 min by month's end. Set against the rest of the year, January is Cát Bà's 7th-clearest and 6th-windiest month. For the whole year in context, see Cát Bà's year-round climate.

Daytime high
19°
12th warmest
Overnight low
16°
1st coldest
Rainfall
40 mm
7.6 wet days
Daylight
10 h 54 min
6:35 AM – 5:27 PM
Cloud cover
71%
7th clearest
Wind
16 km/h
6th windiest
Solar energy
2.74 kWh/m²
Travel score
6.2
out of 10

Cát Bà is town in Vietnam.

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

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 19°C through the month.

A typical January day in Cát Bà reaches about 19°C in the afternoon and slips back to 16°C overnight — a 3°C spread between the day's warmth and the night's chill. On most days the high lands between 15°C and 22°C. Set against its neighbours, January runs about 2°C cooler than December and on par with February.

10°15°20°25°151015202531
Avg high (°C)Avg low (°C)
11917
21917
31917
41917
51917
61917
71917
81917
91916
101916
111916
121916
131916
141916
151916
161816
171816
181816
191816
201816
211816
221816
231816
241816
251816
261816
271816
281816
291816
301816
311816

How January really feels in Cát Bà

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

January sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Cát Bà weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 10th-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 January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 20% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 12% of January, with mostly cloudy or overcast conditions the remaining 69%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14159
23961
33862
43763
53664
63565
73466
83268
93268
103169
112971
122971
132872
142872
152773
162773
172773
182872
192872
202872
212872
222971
232971
242971
252971
263169
273169
283169
293169
303169
313169

Chance of precipitation in January

Any precipitation

Cát Bà gets around 40 mm of rain over 7.6 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 24% and peaks near 25% on the wettest days.

0%10%20%30%40%151015202531
Rain chance (%)
123
223
323
424
524
624
724
824
924
1024
1124
1224
1324
1424
1525
1625
1725
1825
1925
2025
2125
2225
2324
2424
2524
2624
2724
2824
2924
3023
3123

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, January lands in the dry band about 41% of days. Sticky, muggy-or-worse air turns up on roughly 16% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1382026151
2382026161
3381925171
4381925171
5381925181
6391924181
7391924181
8391923181
9391923181
10391922181
11392022181
12402022181
13402022171
14402022171
15412022161
16412122151
17412123150
18422123140
19422123140
20432123130
21432123130
22432024130
23442024130
24441924130
25441924130
26441924130
27441924130
28441924130
29441924130
30431924140
31421924141

Wind in January

Winds average 16 km/h in January.

Across January, daily wind ranges from about 16 km/h on the calmest days to 17 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202531
Wind speed (km/h)Feels
116light breeze
216light breeze
316light breeze
416light breeze
516light breeze
616light breeze
716light breeze
816light breeze
916light breeze
1017light breeze
1117light breeze
1217light breeze
1317light breeze
1417light breeze
1516light breeze
1616light breeze
1716light breeze
1816light breeze
1916light breeze
2016light breeze
2116light breeze
2216light breeze
2316light breeze
2416light breeze
2516light breeze
2616light breeze
2716light breeze
2816light breeze
2916light breeze
3016light breeze
3116light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 10 h 48 min at the start of January to 11 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 18 minutes over January. Sunrise moves from 6:32 AM to 6:34 AM, and sunset from 5:18 PM to 5:37 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
110.86:325:18
210.86:325:18
310.86:335:19
410.86:335:20
510.86:335:20
610.86:345:21
710.86:345:21
810.86:345:22
910.86:345:23
1010.86:345:23
1110.86:355:24
1210.86:355:25
1310.86:355:25
1410.86:355:26
1510.96:355:27
1610.96:355:27
1710.96:355:28
1810.96:355:28
1910.96:355:29
2010.96:355:30
2110.96:355:30
2210.96:355:31
2310.96:355:32
2411.06:355:32
2511.06:355:33
2611.06:355:34
2711.06:345:34
2811.06:345:35
2911.06:345:35
3011.06:345:36
3111.16:345:37

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.74 kWh/m² — the year's lowest.

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 — January's 2.74 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
12.9Moderate
22.8Moderate
32.8Moderate
42.8Moderate
52.8Moderate
62.8Moderate
72.8Moderate
82.7Moderate
92.7Moderate
102.7Moderate
112.7Moderate
122.7Moderate
132.7Moderate
142.7Moderate
152.7Moderate
162.7Moderate
172.7Moderate
182.7Moderate
192.7Moderate
202.7Moderate
212.7Moderate
222.8Moderate
232.8Moderate
242.8Moderate
252.8Moderate
262.8Moderate
272.8Moderate
282.9Moderate
292.9Moderate
302.9Moderate
312.9Moderate
Planning a trip in January

Hazard calendar for Cát Bà

In seasonPeak

In January, Cát Bà sits inside its pacific typhoon 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 January a good time to visit Cát Bà?

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

6.2
Sightseeing
6th-best month of the year
2.5
Beach & pool
12th-best month of the year

January is a reasonable time to visit Cát Bà for sightseeing.

What to pack for Cát Bà in January

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

In January, Cát Bà sees daytime highs around 19°C and nights near 16°C. Little to plan around — just the basics. About 8 days see rain.

Sea temperature near Cát Bà in January

The nearest coast averages about 20°C in January — 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 January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 7 — enough to warrant sun protection. 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 January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January 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
January 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).