This report describes the typical weather at the Custer County Airport (Custer, South Dakota, United States) weather station over the course of an average June. It is based on the historical records from 1999 to 2012. Earlier records are either unavailable or unreliable.
Custer, South Dakota has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by forests (50%), grasslands (44%), and shrublands (5%).
The month of June is characterized by rapidly rising daily high temperatures, with daily highs increasing from 64°F to 76°F over the course of the month, exceeding 84°F or dropping below 53°F only one day in ten.
Over the course of June, the length of the day is essentially constant. The shortest day of the month is June 1 with 15:14 hours of daylight; the longest day is June 21 with 15:28 hours of daylight.
The earliest sunrise is at 5:12am on June 18; the latest sunset is at 8:41pm on June 29; the latest sunrise is at 5:16am on June 30; the earliest sunset is at 8:29pm on June 1.
Daylight saving time is observed in 2012 but it neither starts nor ends in June, so the entire month is in daylight time.
The median cloud cover ranges from 11% (mostly clear) to 25% (mostly clear). The trend is for the sky to be clearing with the median cloud cover decreasing by 14% from the start to the end of the month.
On June 30, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 74% of the time, and overcast or mostly cloudy 24% of the time.
On June 1, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 40% of the time, and clear or mostly clear 59% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around June 3, occurring in 50% of days. Precipitation is least likely around June 30, occurring in 42% of days.
Throughout June, the most common forms of precipitation are light rain, moderate rain, and heavy rain.
Light rain is the most severe precipitation observed during 51% of those days with precipitation. It is most likely around June 5, when it is observed during 25% of all days.
Moderate rain is the most severe precipitation observed during 25% of those days with precipitation. It is most likely around June 14, when it is observed during 12% of all days.
Heavy rain is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around June 18, when it is observed during 9% of all days.
The likelihood of snow falling is highest around June 1, occurring in 5% of days.
Either snow rarely accumulates at this location in June or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 35% (comfortable) to 89% (very humid) over the course of a typical June, rarely dropping below 20% (dry) and reaching as high as 99% (very humid).
The air is driest around June 30, at which time the relative humidity drops below 43% (comfortable) three days out of four; it is most humid around June 3, rising above 85% (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 June, the dew point typically varies from 33°F (dry) to 53°F (very comfortable) and is rarely below 25°F (dry) or above 59°F (comfortable).
Over the course of June typical wind speeds vary from 0 mph to 15 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 8 mph (light breeze) occurs around June 1, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around June 29, at which time the average daily maximum wind speed is 13 mph (moderate breeze).