This report describes the typical weather at the Reykjavík Airport (Reykjavík, Iceland) weather station over the course of an average August. It is based on the historical records from 1979 to 2012. Earlier records are either unavailable or unreliable.
Reykjavík has a humid subarctic continental climate with cool summers and no dry season. The area within 25 mi of this station is covered by oceans and seas (39%), shrublands (34%), forests (19%), and tundra (4%).
The month of August is characterized by gradually falling daily high temperatures, with daily highs around 55°F throughout the month, exceeding 62°F or dropping below 50°F only one day in ten.
Over the course of August, the length of the day is very rapidly decreasing. From the start to the end of the month, the length of the day decreases by 3:14 hours, implying an average day-over-day decrease of 6.3 minutes.
The shortest day of the month is August 31 with 14:37 hours of daylight; the longest day is August 1 with 17:51 hours of daylight.
The earliest sunrise is at 4:37am on August 1; the latest sunset is at 10:28pm on August 1; the latest sunrise is at 6:08am on August 31; the earliest sunset is at 8:45pm on August 31.
Daylight savings time (DST) is not observed in 2012.
The median cloud cover is 90% (mostly cloudy) and does not vary substantially over the course of the month.
On August 16, a representative day, the sky is clear or mostly clear 15% of the time, partly cloudy 15% of the time, and mostly cloudy or overcast 64% of the time.
The average probability that some form of precipitation will be observed in a given day is 72%, with little variation over the course of the month.
Throughout August, the most common forms of precipitation are moderate rain and light rain.
Moderate rain is the most severe precipitation observed during 68% of those days with precipitation. It is most likely around August 31, when it is observed during 52% of all days.
Light rain is the most severe precipitation observed during 17% of those days with precipitation. It is most likely around August 21, when it is observed during 13% of all days.
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 67% (mildly humid) to 92% (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 30, at which time the relative humidity drops below 75% (humid) three days out of four; it is most humid around August 1, rising above 89% (very humid) three days out of four.
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 39°F (dry) to 50°F (dry) and is rarely below 32°F (dry) or above 54°F (very comfortable).
Over the course of August typical wind speeds vary from 3 mph to 18 mph (light air to fresh breeze), rarely exceeding 30 mph (strong breeze).
The highest average wind speed of 12 mph (gentle breeze) occurs around August 31, at which time the average daily maximum wind speed is 18 mph (fresh breeze).
The lowest average wind speed of 10 mph (gentle breeze) occurs around August 3, at which time the average daily maximum wind speed is 17 mph (moderate breeze).