This report describes the typical weather at the Dane County Regional Airport (Madison, Wisconsin, United States) weather station over the course of an average May. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Madison, Wisconsin has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by grasslands (49%), croplands (45%), and lakes and rivers (3%).
The month of May is characterized by rapidly rising daily high temperatures, with daily highs increasing from 64Â°F to 74Â°F over the course of the month, exceeding 84Â°F or dropping below 52Â°F only one day in ten.
Over the course of May, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 60 minutes, implying an average day-over-day increase of 1.9 minutes.
The shortest day of the month is May 1 with 14:09 hours of daylight; the longest day is May 31 with 15:09 hours of daylight.
The earliest sunrise is at 5:21am on May 31; the latest sunset is at 8:29pm on May 31; the latest sunrise is at 5:50am on May 1; the earliest sunset is at 7:59pm 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 ranges from 56% (partly cloudy) to 67% (partly cloudy). The trend is for the sky to be clearing with the median cloud cover decreasing by 11% from the start to the end of the month.
On May 31, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 57% of the time, and overcast or mostly cloudy 42% of the time.
On May 1, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 59% of the time, and clear or mostly clear 40% of the time.
The average probability that some form of precipitation will be observed in a given day is 49%, with little variation over the course of the month.
Throughout May, the most common forms of precipitation are light rain, thunderstorms, and moderate rain.
Light rain is the most severe precipitation observed during 38% of those days with precipitation. It is most likely around May 13, when it is observed during 20% of all days.
Thunderstorms are the most severe precipitation observed during 29% of those days with precipitation. They are most likely around May 31, when it is observed during 17% of all days.
Moderate rain is the most severe precipitation observed during 24% of those days with precipitation. It is most likely around May 7, when it is observed during 12% of all days.
The likelihood of snow falling is highest around May 1, occurring in 6% 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 42% (comfortable) to 90% (very humid) over the course of a typical May, rarely dropping below 25% (dry) and reaching as high as 100% (very humid).
The air is driest around May 1, at which time the relative humidity drops below 49% (comfortable) three days out of four; it is most humid around May 31, rising above 86% (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 May, the dew point typically varies from 33Â°F (dry) to 56Â°F (comfortable) and is rarely below 23Â°F (dry) or above 67Â°F (muggy).
Over the course of May typical wind speeds vary from 0 mph to 16 mph (calm to moderate breeze), rarely exceeding 23 mph (fresh breeze).
The highest average wind speed of 10 mph (gentle breeze) occurs around May 1, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 8 mph (gentle breeze) occurs around May 29, at which time the average daily maximum wind speed is 15 mph (moderate breeze).