This report describes the typical weather at the Reykjavík Airport (Reykjavík, Iceland) weather station over the course of an average July. 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 July is characterized by essentially constant daily high temperatures, with daily highs around 56°F throughout the month, exceeding 62°F or dropping below 51°F only one day in ten.
Over the course of July, 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 2:46 hours, implying an average day-over-day decrease of 5.4 minutes.
The shortest day of the month is July 31 with 18:03 hours of daylight; the longest day is July 1 with 20:49 hours of daylight.
The earliest sunrise is at 3:07am on July 1; the latest sunset is at 11:56pm on July 1; the latest sunrise is at 4:31am on July 31; the earliest sunset is at 10:34pm on July 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 July 16, a representative day, the sky is clear or mostly clear 14% of the time, partly cloudy 15% of the time, and mostly cloudy or overcast 65% of the time.
The average probability that some form of precipitation will be observed in a given day is 70%, with little variation over the course of the month.
Throughout July, the most common forms of precipitation are moderate rain, light rain, and drizzle.
Moderate rain is the most severe precipitation observed during 63% of those days with precipitation. It is most likely around July 31, when it is observed during 47% of all days.
Light rain is the most severe precipitation observed during 18% of those days with precipitation. It is most likely around July 1, when it is observed during 14% of all days.
Drizzle is the most severe precipitation observed during 14% of those days with precipitation. It is most likely around July 6, when it is observed during 11% of all days.
Either snow is exceptionally unlikely to fall at this location in July or this station does not reliably report precipitation types.
The relative humidity typically ranges from 65% (mildly humid) to 92% (very humid) over the course of a typical July, rarely dropping below 51% (mildly humid) and reaching as high as 100% (very humid).
The air is driest around July 1, at which time the relative humidity drops below 74% (humid) three days out of four; it is most humid around July 28, 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 July, the dew point typically varies from 41°F (dry) to 50°F (dry) and is rarely below 35°F (dry) or above 54°F (very comfortable).
Over the course of July typical wind speeds vary from 3 mph to 18 mph (light air to moderate breeze), rarely exceeding 26 mph (strong breeze).
The highest average wind speed of 11 mph (gentle breeze) occurs around July 13, at which time the average daily maximum wind speed is 17 mph (moderate breeze).
The lowest average wind speed of 10 mph (gentle breeze) occurs around July 27, at which time the average daily maximum wind speed is 16 mph (moderate breeze).