This report describes the typical weather at the Edmonton/Namao Heliport (Edmonton, Alberta, Canada) weather station over the course of an average May. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Edmonton, Alberta has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by grasslands (56%), croplands (33%), built-up areas (4%), forests (4%), and lakes and rivers (3%).
The month of May is characterized by rapidly rising daily high temperatures, with daily highs ranging from 55°F to 65°F over the course of the month, exceeding 76°F or dropping below 43°F only one day in ten.
Over the course of May, the length of the day is rapidly increasing. From the start to the end of the month, the length of the day increases by 1:33 hours, implying an average day-over-day increase of 3.0 minutes.
The shortest day of the month is May 1 with 15:08 hours of daylight; the longest day is May 31 with 16:41 hours of daylight.
The earliest sunrise is at 5:11am on May 31; the latest sunset is at 9:52pm on May 31; the latest sunrise is at 5:58am on May 1; the earliest sunset is at 9:06pm on May 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in May, so the entire month is in daylight time.
The median cloud cover is 43% (partly cloudy) and does not vary substantially over the course of the month.
On May 16, a representative day, the sky is clear or mostly clear 51% of the time, partly cloudy 7% of the time, and mostly cloudy or overcast 41% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around May 30, occurring in 55% of days. Precipitation is least likely around May 1, occurring in 45% of days.
Throughout May, the most common forms of precipitation are light rain, moderate rain, and light snow.
Light rain is the most severe precipitation observed during 59% of those days with precipitation. It is most likely around May 28, when it is observed during 34% of all days.
Moderate rain is the most severe precipitation observed during 18% of those days with precipitation. It is most likely around May 29, when it is observed during 12% of all days.
Light snow is the most severe precipitation observed during 11% of those days with precipitation. It is most likely around May 1, when it is observed during 10% of all days.
The likelihood of snow falling is highest around May 1, occurring in 13% of days.
Either snow rarely accumulates at this location in May or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 33% (comfortable) to 84% (humid) over the course of a typical May, rarely dropping below 20% (dry) and reaching as high as 98% (very humid).
The air is driest around May 9, at which time the relative humidity drops below 40% (comfortable) three days out of four; it is most humid around May 31, rising above 75% (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 May, the dew point typically varies from 22°F (dry) to 44°F (dry) and is rarely below 11°F (dry) or above 51°F (very comfortable).
Over the course of May typical wind speeds vary from 2 mph to 18 mph (light air to fresh breeze), rarely exceeding 26 mph (strong breeze).
The highest average wind speed of 10 mph (gentle breeze) occurs around May 2, at which time the average daily maximum wind speed is 18 mph (moderate breeze).
The lowest average wind speed of 9 mph (gentle breeze) occurs around May 31, at which time the average daily maximum wind speed is 18 mph (moderate breeze).