Climate in the Red River Delta

Average daytime and nighttime temperatures

All climate diagrams on this site result from the collected data from three measuring weather stations in Red River Delta.
All data correspond to the average monthly values of the last 20 years.

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The Red River Delta is one of the coldest regions in Vietnam with an average daily high temperature of only 28 degrees. High humidity and hot temperatures make the weather pleasant at times but also tropical humid. For 9 months, the average temperatures are over 25 degrees. Pleasant water temperatures of up to 29 degrees even invite you to bathe in the warm season. Because of the lower temperatures, the best time for traveling is from December to March. Try to avoid the rainy season from July to September.
Overview: Climate in Vietnam
Daylengths and sun positions in Vietnam
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Sunshine hours per day
The number of hours of sunshine refers to the time when the sun is actually visible. That is, without any obstruction of visibility by clouds, fog or mountains. With 6 hours per day, June is the sunniest month in the region of Red River Delta. In March, the sun shines the least.
Rain days per month
A rain day is a day on which at least 0.1 mm precipitation (=0.1 liter) per square meter falls. This can be rain, snow, hail or even dew. So it does not have to rain the whole day. With 16 rain days, August offers the most rain days, while December has the fewest.
Precipitation amount in mm/day
The amount of precipitation is measured in millimeters per square meter. Thus, at two mm/day, two liters of water fall on one square meter within 24 hours. With only 0.7 mm, the least amount of rain falls in December. August, on the other hand, has the most rain.
Water temperatures in °C
Water temperature depends not only on solar radiation within the same region, but also on ocean currents. For example, depending on the season, cold or warm water masses are moved from other areas. The warmest water temperatures in the Red River Delta are in June, when the water is 29 °C.
Relative humidity in %
Warm air can absorb more moisture than cold air. The relative humidity indicates how much moisture can be physically contained in the air. At high humidity, a person feels uncomfortable and perceives this as oppressive. In general, a relative humidity of 40-60% feels pleasant. With humidity averaging 88%, March is the most uncomfortable. In November, on the other hand, it is easier to endure.
Absolute humidity in g/m³
In warm months, there is also a higher absolute humidity almost everywhere. At a temperature of 25°C, air can absorb up to 23 grams of water per cubic meter. At 20°C, it is only 17.3 grams. A relative humidity of 40% at 25°C thus corresponds to an absolute humidity of 9.2 grams of water. From a proportion of approx. 13.5 grams, humans perceive the air as muggy. This limit is reached for 10 months in the Red River Delta, although these are average values, and a month is rarely completely or not at all humid.
The "Humidex" (humidity index) is an index of well-being in warmer areas, calculated from the air temperature, relative humidity and dew point. The index corresponds approximately to the temperature felt. At high temperatures, the body transports heat away by sweating. At high humidity, the ambient air can only absorb a small amount of sweat and thus one feels uncomfortable. An index of 20-29 is considered comfortable. Up to 39, people perceive the air as slightly uncomfortable, and above 40, as very uncomfortable. Values above 45 are dangerous in the long run and often lead to heat stroke.
Map of Red River Delta

Most important cities in the region »Red River Delta«

As the capital region, it is arguably the most important part of Vietnam. Alone 2 major cities with over 600,000 inhabitants are located here. The region has a west-east extension of about 160 km and over 120 km from north to south.

It consists of the ten provinces Bac Ninh, H, Ha Noi, Hai Duong, Hai Phong, Hung Yen, Nam Dinh, Ninh B, Th and Vinh Phuc.

CityPopulationGeo position
Hanoi4,678,19821° 1' 28"N105° 50' 28"E
Haiphong602,69520° 51' 53"N106° 41' 0"E
Thanh Pho Nam Dinh193,49920° 26' 2"N106° 10' 38"E
Thanh Pho Hai Duong58,03020° 56' 28"N106° 19' 59"E
Thanh Pho Thai Binh53,07120° 26' 60"N106° 20' 24"E
Ha Dong50,87720° 58' 17"N105° 46' 44"E
Bac Ninh43,56421° 11' 10"N106° 4' 35"E
Son Tay40,63621° 8' 26"N105° 30' 25"E
Hung Yen40,27320° 38' 47"N106° 3' 4"E
Thanh Pho Ninh Binh36,86420° 15' 29"N105° 58' 47"E
Thanh Pho Phu Ly31,80120° 32' 43"N105° 54' 44"E
Cát Bà30,00020° 43' 40"N107° 2' 53"E
Vinh Yen17,87621° 18' 32"N105° 36' 18"E

Data basis: German Weather Service, individual values averaged and supplemented by own elements. Data on cities and inhabitants:, United Nations Statistics Division and own research.
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