Cát Bà, Vietnam Climate
The warmest month is July, with an average high of 30°C; the coldest is January, with an average low of 17°C. A normal year brings 1662 mm of precipitation.
Temperature through the year
The normal daily high and low. The line marks today.
- Normal low
- Normal high
- Reanalysis extreme high
- Reanalysis extreme low
Normals for Sep 25
- Normal high
- 29°C
- Normal low
- 27°C
- Reanalysis high
- 31°Cin 2015
- Reanalysis low
- 24°Cin 1997
- Chance of a wet day
- 59%
- Daylight
- 12 h 05 min
Month by month
Averages for 1991-2020. Wet days have at least 1 mm of precipitation in the reanalysis. Each month links to its own page.
| Month | Avg high | Avg low | Warmest | Coldest | Precipitation | Wet days |
|---|---|---|---|---|---|---|
| January | 19°C | 17°C | 27°C (1998) | 8°C (2016) | 34 mm | 6.2 |
| February | 20°C | 17°C | 27°C (2010) | 8°C (1996) | 23 mm | 5.7 |
| March | 22°C | 19°C | 29°C (2020) | 11°C (2006) | 47 mm | 9.3 |
| April | 25°C | 23°C | 32°C (2012) | 16°C (1991) | 60 mm | 12.0 |
| May | 28°C | 26°C | 33°C (1992) | 20°C (1991) | 171 mm | 18.6 |
| June | 30°C | 28°C | 34°C (2018) | 24°C (1992) | 222 mm | 24.0 |
| July | 30°C | 29°C | 34°C (2015) | 26°C (1992) | 285 mm | 24.8 |
| August | 30°C | 28°C | 34°C (2011) | 25°C (2002) | 338 mm | 24.8 |
| September | 30°C | 27°C | 33°C (2011) | 21°C (1997) | 270 mm | 21.0 |
| October | 28°C | 25°C | 31°C (2014) | 19°C (2010) | 127 mm | 15.5 |
| November | 25°C | 22°C | 29°C (2006) | 14°C (2009) | 57 mm | 9.0 |
| December | 21°C | 18°C | 27°C (2018) | 8°C (1991) | 28 mm | 6.2 |
| Year | 26°C | 23°C | 1662 mm | 177 |
Precipitation
Rain and melted snow together. The chance of a wet day is the share of days with at least 1 mm of precipitation in the reanalysis.
1662 mm in a normal year, most in August.
Chance of a wet day
- Chance of a wet day
Humidity and comfort
NASA POWER reanalysis, 1991-2020, for the grid cell around Cát Bà.
The muggiest month is July, when 100 percent of days are muggy or worse, with a mean dew point of 18°C or more.
| Month | Dew point | Humidity | Dry | Comfortable | Humid | Muggy | Oppressive | Miserable |
|---|---|---|---|---|---|---|---|---|
| January | 15°C | 81% | 37% | 19% | 23% | 20% | 1% | 0% |
| February | 16°C | 84% | 24% | 19% | 25% | 28% | 4% | 0% |
| March | 18°C | 87% | 7% | 12% | 19% | 40% | 21% | 0% |
| April | 22°C | 88% | 0% | 3% | 10% | 20% | 50% | 17% |
| May | 25°C | 86% | 0% | 0% | 1% | 7% | 20% | 72% |
| June | 26°C | 85% | 0% | 0% | 0% | 0% | 3% | 96% |
| July | 26°C | 84% | 0% | 0% | 0% | 0% | 1% | 99% |
| August | 26°C | 83% | 0% | 0% | 0% | 0% | 1% | 99% |
| September | 25°C | 80% | 0% | 0% | 0% | 6% | 18% | 76% |
| October | 22°C | 77% | 0% | 2% | 7% | 24% | 45% | 22% |
| November | 19°C | 76% | 5% | 15% | 25% | 26% | 27% | 4% |
| December | 15°C | 76% | 28% | 24% | 25% | 16% | 6% | 0% |
Comfort is judged by the day's mean dew point: dry below 13°C, comfortable to 16°C, humid to 18°C, muggy to 21°C, oppressive to 24°C, miserable above.
Clouds
Average share of the sky covered, from satellite (CERES and GEWEX SRB) by way of NASA POWER, 1991-2020.
The clearest month is October, with the sky 58 percent covered on average; the cloudiest is June, at 82 percent.
Wind
The mean wind speed over the whole day, from the MERRA-2 reanalysis by way of NASA POWER. Gusts run well above it.
The windiest month is December, averaging 20.9 km/h at 10 meters (33 feet) above the ground.
Daylight and sunshine
The longest day is Jun 18, with 13 h 24 min of daylight; the shortest is Dec 17, with 10 h 52 min.
- Day length
Solar energy
Average daily sunshine reaching the ground on a flat surface, in kilowatt-hours per square meter, clouds included.
Month pages
The weather in Cát Bà in each month, day by day.
What this means
A normal is the average of the thirty years 1991 to 2020, the period the World Meteorological Organization and NOAA use for comparison. It is an average, not a forecast: most days depart from it, and some by a long way.
Where no station record is within reach, the extremes shown are the highest and lowest the reanalysis produced for the date in 1991-2020, not measured records.
Cloud, humidity, wind and sunshine come from a reanalysis: a weather model run over the past with every observation fed in, averaged over a grid cell about 50 km across. It is consistent everywhere on Earth; it smooths local detail such as a lake shore or a valley.
More for this place
Nearby
Sources
Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.