This report describes the typical weather at the Mackinac Island (Mackinac Island, Michigan, United States) weather station over the course of an average October. It is based on the historical records from 1997 to 2012. Earlier records are either unavailable or unreliable.
Mackinac Island, Michigan has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by oceans and seas (44%), forests (39%), and croplands (15%).
The month of October is characterized by rapidly falling daily high temperatures, with daily highs decreasing from 61°F to 48°F over the course of the month, exceeding 70°F or dropping below 40°F only one day in ten.
Over the course of October, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1:33 hours, implying an average day-over-day decrease of 3.0 minutes.
The shortest day of the month is October 31 with 10:07 hours of daylight; the longest day is October 1 with 11:40 hours of daylight.
The earliest sunrise is at 7:38am on October 1; the latest sunset is at 7:18pm on October 1; the latest sunrise is at 8:18am on October 31; the earliest sunset is at 6:26pm on October 31.
Daylight saving time is observed in 2012 but it neither starts nor ends in October, so the entire month is in daylight time.
The median cloud cover ranges from 55% (partly cloudy) to 83% (mostly cloudy). The trend is for the sky to be becoming rapidly cloudier with the median cloud cover increasing by 28% from the start to the end of the month.
On October 1, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 52% of the time, and overcast or mostly cloudy 45% of the time.
On October 31, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 72% of the time, and clear or mostly clear 27% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around October 31, occurring in 55% of days. Precipitation is least likely around October 1, occurring in 46% of days.
Throughout October, the most common forms of precipitation are moderate rain, light rain, light snow, and heavy rain.
Moderate rain is the most severe precipitation observed during 46% of those days with precipitation. It is most likely around October 11, when it is observed during 24% of all days.
Light rain is the most severe precipitation observed during 20% of those days with precipitation. It is most likely around October 5, when it is observed during 11% of all days.
Light snow is the most severe precipitation observed during 16% of those days with precipitation. It is most likely around October 31, when it is observed during 16% of all days.
Heavy rain is the most severe precipitation observed during 12% of those days with precipitation. It is most likely around October 1, when it is observed during 9% of all days.
The likelihood of snow falling is highest around October 31, occurring in 19% of days.
Either snow rarely accumulates at this location in October or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 61% (mildly humid) to 94% (very humid) over the course of a typical October, rarely dropping below 45% (comfortable) and reaching as high as 100% (very humid).
The air is driest around October 10, at which time the relative humidity drops below 70% (humid) three days out of four; it is most humid around October 2, 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 October, the dew point typically varies from 32°F (dry) to 52°F (very comfortable) and is rarely below 23°F (dry) or above 60°F (comfortable).
Over the course of October typical wind speeds vary from 0 mph to 11 mph (calm to gentle breeze), rarely exceeding 17 mph (moderate breeze).
The highest average wind speed of 6 mph (light breeze) occurs around October 31, at which time the average daily maximum wind speed is 10 mph (gentle breeze).
The lowest average wind speed of 5 mph (light breeze) occurs around October 1, at which time the average daily maximum wind speed is 10 mph (gentle breeze).