Average Weather in August in Hanoi Vietnam
Daily high temperatures are around 90°F, rarely falling below 83°F or exceeding 96°F.
Daily low temperatures are around 79°F, rarely falling below 75°F or exceeding 82°F.
For reference, on June 27, the hottest day of the year, temperatures in Hanoi typically range from 80°F to 92°F, while on January 19, the coldest day of the year, they range from 57°F to 67°F.
Average High and Low Temperature in August
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on August. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in August
Laguna Heights, Texas, United States (8,843 miles away) and St. Petersburg, Florida, United States (9,028 miles) are the far-away foreign places with temperatures most similar to Hanoi (view comparison).
The month of August in Hanoi experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 90% to 83%.
The clearest day of the month is August 31, with clear, mostly clear, or partly cloudy conditions 17% of the time.
For reference, on June 16, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 93%, while on February 22, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 70%.
Cloud Cover Categories in August
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Hanoi, the chance of a wet day over the course of August is essentially constant, remaining around 55% throughout.
For reference, the year's highest daily chance of a wet day is 57% on August 25, and its lowest chance is 5% on January 31.
Probability of Precipitation in August
To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during August in Hanoi is gradually decreasing, starting the month at 8.7 inches, when it rarely exceeds 15.3 inches or falls below 2.5 inches, and ending the month at 8.4 inches, when it rarely exceeds 13.6 inches or falls below 3.3 inches.
The highest average 31-day accumulation is 8.9 inches on August 15.
Average Monthly Rainfall in August
Over the course of August in Hanoi, the length of the day is decreasing. From the start to the end of the month, the length of the day decreases by 31 minutes, implying an average daily decrease of 1 minute, 2 seconds, and weekly decrease of 7 minutes, 15 seconds.
The shortest day of the month is August 31, with 12 hours, 34 minutes of daylight and the longest day is August 1, with 13 hours, 5 minutes of daylight.
Hours of Daylight and Twilight in August
The earliest sunrise of the month in Hanoi is 5:30 AM on August 1 and the latest sunrise is 10 minutes later at 5:39 AM on August 31.
The latest sunset is 6:35 PM on August 1 and the earliest sunset is 22 minutes earlier at 6:13 PM on August 31.
Daylight saving time is not observed in Hanoi during 2018.
For reference, on June 21, the longest day of the year, the Sun rises at 5:15 AM and sets 13 hours, 25 minutes later, at 6:40 PM, while on December 21, the shortest day of the year, it rises at 6:28 AM and sets 10 hours, 51 minutes later, at 5:20 PM.
Sunrise & Sunset with Twilight in August
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The chance that a given day will be muggy in Hanoi is essentially constant during August, remaining around 100% throughout.
The highest chance of a muggy day during August is 100% on August 10.
For reference, on August 4, the muggiest day of the year, there are muggy conditions 100% of the time, while on January 21, the least muggy day of the year, there are muggy conditions 15% of the time.
Humidity Comfort Levels in August
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Hanoi is essentially constant during August, remaining within 0.2 miles per hour of 5.3 miles per hour throughout.
For reference, on March 11, the windiest day of the year, the daily average wind speed is 7.9 miles per hour, while on August 19, the calmest day of the year, the daily average wind speed is 5.1 miles per hour.
The lowest daily average wind speed during August is 5.1 miles per hour on August 20.
Average Wind Speed in August
Wind Direction in August
Hanoi is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in Hanoi is essentially constant during August, remaining around 85°F throughout.
The highest average surface water temperature during August is 85°F on August 20.
Average Water Temperature in August
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
Temperatures in Hanoi are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season in August
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
The average accumulated growing degree days in Hanoi are very rapidly increasing during August, increasing by 976°F, from 5,148°F to 6,124°F, over the course of the month.
Growing Degree Days in August
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy in Hanoi is essentially constant during August, remaining within 0.2 kWh of 4.4 kWh throughout.
The lowest average daily incident shortwave solar energy during August is 4.2 kWh on August 3.
Average Daily Incident Shortwave Solar Energy in August
For the purposes of this report, the geographical coordinates of Hanoi are 21.024 deg latitude, 105.841 deg longitude, and 39 ft elevation.
The topography within 2 miles of Hanoi contains only modest variations in elevation, with a maximum elevation change of 108 feet and an average elevation above sea level of 46 feet. Within 10 miles also contains only modest variations in elevation (217 feet). Within 50 miles contains only modest variations in elevation (5,387 feet).
The area within 2 miles of Hanoi is covered by cropland (43%), artificial surfaces (29%), and water (14%), within 10 miles by cropland (60%) and grassland (12%), and within 50 miles by cropland (49%) and trees (23%).
This report illustrates the typical weather in Hanoi year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There is only a single weather station, Noi Bai International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of Hanoi.
At a distance of 22 kilometers from Hanoi, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.
The station records are corrected for the elevation difference between the station and Hanoi according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.