Average Weather In August For Galveston, Texas, USA

Location

This report describes the typical weather at the Scholes International Airport at Galveston (Galveston, Texas, United States) 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.

Galveston, Texas has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by oceans and seas (76%) and croplands (21%).

Temperature

The month of August is characterized by essentially constant daily high temperatures, with daily highs around 90°F throughout the month, exceeding 93°F or dropping below 85°F only one day in ten.

Daily High and Low Temperature in August

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).
Daily low temperatures are around 80°F, falling below 76°F or exceeding 83°F only one day in ten.

Fraction of Time Spent in Various Temperature Bands in August

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).

Sun

Over the course of August, the length of the day is gradually decreasing. From the start to the end of the month, the length of the day decreases by 46 minutes, implying an average day-over-day decrease of 1.5 minutes.

The shortest day of the month is August 31 with 12:45 hours of daylight; the longest day is August 1 with 13:31 hours of daylight.

Daily Hours of Daylight and Twilight in August

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 6:40am on August 1; the latest sunset is at 8:11pm on August 1; the latest sunrise is at 6:57am on August 31; the earliest sunset is at 7:42pm on August 31.

Daylight saving time is observed in 2012 but it neither starts nor ends in August, so the entire month is in daylight time.

Daily Sunrise & Sunset with Twilight and Daylight Saving Time 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 transitions to and from daylight saving time are indicated by the "DST" labels.

Clouds

The median cloud cover is 11% (mostly clear) and does not vary substantially over the course of the month.

Median Cloud Cover in August

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 68% of the time, partly cloudy 7% of the time, and mostly cloudy or overcast 16% 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.

Precipitation

The average probability that some form of precipitation will be observed in a given day is 40%, with little variation over the course of the month.

Probability of Precipitation at Some Point in the Day in August

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, light rain, and moderate rain.

Thunderstorms are the most severe precipitation observed during 62% of those days with precipitation. They are most likely around August 15, when it is observed during 26% of all days.

Light rain is the most severe precipitation observed during 21% of those days with precipitation. It is most likely around August 25, when it is observed during 9% of all days.

Moderate rain is the most severe precipitation observed during 10% of those days with precipitation. It is most likely around August 7, when it is observed during 4% of all days.

Types of Precipitation Throughout August

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

Snow

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

Humidity

The relative humidity typically ranges from 59% (mildly humid) to 86% (very humid) over the course of a typical August, rarely dropping below 47% (comfortable), or exceeding 95% (very humid).

The air is driest around August 30, at which time the relative humidity drops below 65% (mildly humid) three days out of four; it is most humid around August 31, rising above 81% (humid) three days out of four.

Relative Humidity in August

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

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 71°F (muggy) to 77°F (oppressive) and is rarely below 66°F (muggy) or above 79°F (oppressive).

Dew Point in August

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).

Wind

Over the course of August typical wind speeds vary from 2 mph to 15 mph (light air to moderate breeze), rarely exceeding 21 mph (fresh breeze).

The highest average wind speed of 10 mph (gentle breeze) occurs around August 5, at which time the average daily maximum wind speed is 15 mph (moderate breeze).

The lowest average wind speed of 9 mph (gentle breeze) occurs around August 25, at which time the average daily maximum wind speed is 14 mph (moderate breeze).

Wind Speed in August

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).
The wind is most often out of the south (21% of the time), south east (21% of the time), east (13% of the time), and north (12% of the time). The wind is least often out of the west (4% of the time), south west (4% of the time), and north west (4% of the time).

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.