This report describes the typical weather at the Noi Bai International Airport (Hanoi, Vietnam) weather station over the course of an average August. It is based on the historical records from 1992 to 2012. Earlier records are either unavailable or unreliable.

Hanoi has a warm temperate climate with dry winters and hot summers. The area within 25 mi of this station is covered by croplands (91%), grasslands (4%), and lakes and rivers (3%).

The month of August is characterized by essentially constant daily high temperatures, with daily highs around 90°F throughout the month, exceeding 95°F or dropping below 85°F only one day in ten.

Daily High and Low Temperature in August

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The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Fraction of Time Spent in Various Temperature Bands in August

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The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Over the course of August, the length of the day is gradually decreasing. The shortest day of the month is August 31 with 12:34 hours of daylight; the longest day is August 1 with 13:05 hours of daylight.

Daily Hours of Daylight and Twilight in August

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The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.

The earliest sunrise is at 5:31am on August 2; the latest sunset is at 6:36pm on August 1; the latest sunrise is at 5:40am on August 31; the earliest sunset is at 6:14pm on August 31.

Daylight savings time (DST) is not observed in 2012.

Daily Sunrise & Sunset with Twilight in August

The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

The median cloud cover is 88% (mostly cloudy) and does not vary substantially over the course of the month.

Median Cloud Cover in August

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The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

On August 16, a representative day, the sky is clear or mostly clear 10% of the time, partly cloudy 13% of the time, and mostly cloudy or overcast 67% of the time.

Cloud Cover Types in August

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around August 1, occurring in 69% of days. Precipitation is least likely around August 31, occurring in 62% of days.

Probability of Precipitation at Some Point in the Day in August

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The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

Throughout August, the most common forms of precipitation are thunderstorms, moderate rain, and light rain.

Thunderstorms are the most severe precipitation observed during 70% of those days with precipitation. They are most likely around August 3, when it is observed during 51% of all days.

Moderate rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around August 31, when it is observed during 13% of all days.

Light rain is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around August 31, when it is observed during 9% of all days.

Types of Precipitation Throughout August

Relative frequency of various types of precipitation over the course of a typical August.

Either snow is exceptionally unlikely to fall at this location in August or this station does not reliably report precipitation types.

The relative humidity typically ranges from 65% (mildly humid) to 98% (very humid) over the course of a typical August, rarely dropping below 53% (mildly humid) and reaching as high as 100% (very humid).

The air is driest around August 29, at which time the relative humidity drops below 71% (humid) three days out of four; it is most humid around August 21, rising above 95% (very humid) three days out of four.

Relative Humidity in August

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The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.

Over the course of a typical August, the dew point typically varies from 74°F (very muggy) to 82°F (very oppressive) and is rarely below 71°F (muggy) or above 85°F (very oppressive).

Dew Point in August

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The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Over the course of August typical wind speeds vary from 0 mph to 10 mph (calm to gentle breeze), rarely exceeding 16 mph (moderate breeze).

The highest average wind speed of 5 mph (light breeze) occurs around August 1, at which time the average daily maximum wind speed is 10 mph (gentle breeze).

The lowest average wind speed of 5 mph (light breeze) occurs around August 30, at which time the average daily maximum wind speed is 10 mph (gentle breeze).

Wind Speed in August

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The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind Directions in August

The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Fraction of Time Spent with Various Wind Directions in August

The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.