Cát Bà weather in April

In April, Cát Bà sees average daytime highs of 25°C and overnight lows near 23°C, with 52 mm of rain across 7.7 wet days and about 12.5 hours of daylight. It is the 7th-warmest and 8th-wettest month of the year here.

Highs climb over the month, from about 23°C in the first days to 26°C by the end. The sky is clear or mostly clear about 22% of the time in April, and the air most often feels oppressive.

Daylight stretches from about 12 h 12 min at the start of April to 12 h 42 min by month's end. Set against the rest of the year, April is Cát Bà's 4th-clearest and 9th-windiest month. For the whole year in context, see Cát Bà's year-round climate.

Daytime high
25°
7th warmest
Overnight low
23°
6th coldest
Rainfall
52 mm
7.7 wet days
Daylight
12 h 30 min
5:38 AM – 6:06 PM
Cloud cover
64%
4th clearest
Wind
15 km/h
9th windiest
Solar energy
4.96 kWh/m²
Travel score
7.0
out of 10

Cát Bà is town in Vietnam.

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

Temperature in April

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 23°C in the first days to 26°C by the end.

A typical April day in Cát Bà reaches about 25°C in the afternoon and slips back to 23°C overnight — a 2°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 27°C. Set against its neighbours, April runs about 3°C warmer than March and about 4°C cooler than May.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12321
22321
32321
42321
52321
62321
72422
82422
92422
102422
112422
122422
132422
142522
152523
162523
172523
182523
192523
202523
212523
222624
232624
242624
252624
262624
272624
282624
292624
302724

How April really feels in Cát Bà

Once humidity and wind are folded in, April 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

April 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 April compares with the rest of the year at a glance. April is the 7th-warmest and 8th-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 April

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 22% of the time in April.

Beyond those clear spells, partly cloudy skies cover about 20% of April, with mostly cloudy or overcast conditions the remaining 58%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
13268
23367
33466
43466
53565
63763
73763
83862
93862
103961
114060
124159
134258
144357
154456
164555
174555
184555
194654
204555
214654
224654
234654
244654
254753
264753
274654
284654
294654
304555

Chance of precipitation in April

Any precipitation

Cát Bà gets around 52 mm of rain over 7.7 wet days in April. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 27% and peaks near 36% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%50%151015202530
Rain chance (%)
127
227
327
427
527
626
726
825
925
1025
1124
1224
1324
1424
1524
1624
1724
1824
1925
2025
2126
2226
2327
2428
2529
2630
2732
2833
2935
3036

Humidity in April

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, April lands in the oppressive band about 50% of days. Sticky, muggy-or-worse air turns up on roughly 84% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1571639330
2461539360
3461537381
4461535391
5361434421
6361432441
7361431461
8361329481
9261328502
10261226522
11261225523
12251123563
13251122564
14251021575
15151020586
16151019578
1714918599
18149185810
19148175812
20138175714
21137165815
22037165717
23026155720
24026155522
25026145325
26025145128
27025134931
28015134734
29015134436
30015134239

Wind in April

Winds average 15 km/h in April.

Across April, daily wind ranges from about 15 km/h on the calmest days to 16 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2916light breeze
3016light breeze

Sunrise & sunset in April

DaylightNight

Daylight runs from about 12 h 12 min at the start of April to 12 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 30 minutes over April. Sunrise moves from 5:51 AM to 5:27 AM, and sunset from 6:02 PM to 6:11 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.25:516:02
212.25:506:02
312.25:496:02
412.25:486:03
512.35:476:03
612.35:476:03
712.35:466:04
812.35:456:04
912.35:446:04
1012.45:436:04
1112.45:426:05
1212.45:416:05
1312.45:406:05
1412.45:396:06
1512.55:396:06
1612.55:386:06
1712.55:376:07
1812.55:366:07
1912.55:356:07
2012.65:356:08
2112.65:346:08
2212.65:336:08
2312.65:326:09
2412.65:316:09
2512.65:316:09
2612.75:306:10
2712.75:296:10
2812.75:296:10
2912.75:286:11
3012.75:276:11

Solar energy in April

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in April, about 4.96 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 — April's 4.96 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
14.3Bright
24.3Bright
34.3Bright
44.4Bright
54.4Bright
64.5Bright
74.5Bright
84.6Bright
94.6Bright
104.7Bright
114.8Bright
124.8Bright
134.9Bright
144.9Bright
155.0Bright
165.0Bright
175.1Bright
185.1Bright
195.2Bright
205.2Bright
215.3Bright
225.3Bright
235.3Bright
245.3Bright
255.4Bright
265.4Bright
275.4Bright
285.4Bright
295.4Bright
305.4Bright
Planning a trip in April

Hazard calendar for Cát Bà

In seasonPeak

In April, 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 April a good time to visit Cát Bà?

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

7.0
Sightseeing
2nd-best month of the year
6.1
Beach & pool
3rd-best month of the year

April is one of the better times to visit Cát Bà for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Cát Bà in April

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

In April, Cát Bà sees daytime highs around 25°C and nights near 23°C. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

Sea temperature near Cát Bà in April

The nearest coast averages about 23°C in April — 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 April

LowModerateHighVery highExtreme

Clear-sky midday UV in April peaks around 8 (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 April

GoodModeratePoorUnhealthyVery unhealthy

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