What Are The Average Weather Conditions For Grandma’s Marathon? Full Weather History Breakdown

People who live in the Twin Ports area know that weather can vary greatly, no matter the season. We can thank geography, topography, and Lake Superior for the huge differences in weather that often occur from day to day. In this area full of unpredictable weather, what are the average conditions for Grandma's Marathon?

According to historical data reported by marathon officials, the "average" marathon day weather is mostly clear with a temperature of 55.6 degrees. The coldest marathon conditions on record were in 1991, when 39 degrees was recorded. The warmest marathon day weather is a tie between 1977 (inaugural year) and 2009, with a reported temperature of 68 degrees.

Here is a full breakdown of the historical weather conditions, as reported by Grandma's Marathon:

1977 (June 25) - 68 F clear

1978 (June 24) - 58 F cloudy

1979 (June 23) - 66 F cloudy

1980 (June 21) - 58 F cloudy, intermittent showers

1981 (June 20) - 52 F overcast, fog

1982 (June 19) - 56 F partly cloudy, light precipitation

1983 (June 11) - 59 F clear

1984 (June 16) - 48 F cloudy, dense fog, occasional mist

1985 (June 15) - 47 F mostly cloudy

1986 (June 21) - 52 F mostly cloudy

1987 (June 20) - 59 F mostly sunny

1988 (June 11) - 61 F clear

1989 (June 17) - 42 F clear

1990 (June 23) - 64 F clear

1991 (June 22) - 39 F clear

1992 (June 20) - 44 F clear/partly cloudy

1993 (June 19) - 50 F cloudy

1994 (June 18) - 60 F clear

1995 (June 17) - 55 F clear

1996 (June 22) - 47 F partly sunny

1997 (June 21) - 56 F clear

1998 (June 20) - 55 F fog early, light rain, then clearing

1999 (June 19) - 53 F overcast

2000 (June 17) - 42 F clear

2001 (June 16) - 55 F clear

2002 (June 22) - 50 F overcast, early rain

2003 (June 21) - 57 F clear

2004 (June 19) - 54 F clear

2005 (June 18) - 57 F clear

2006 (June 17) - 64 F hazy, humid

2007 (June 16) - 66 F clear, humid

2008 (June 21) - 61 F partly cloudy

2009 (June 20) - 68 F clear

2010 (June 19) - 64 F partly cloudy

2011 (June 18) - 49 F cloudy, tailwind

2012 (June 16) - 65 F overcast, tailwind

2013 (June 22) - 55 F cloudy, fog, occasional mist, tailwind

2014 (June 21) - 48 F cloudy, fog, occasional mist, tailwind

2015 (June 20) - 62 F cloudy, fog, mist early clearing through morning, tailwind

2016 (June 18) - 65 F clear, humid, slight headwind

2017 (June 17) - 57 F low / 75 high cloudy

2018 (June 16) - 53 F low / 74 F high overcast, light rain at start

2019 (June 22) - 50 F low / 73 F high clear, windy

2020 - Virtual event due to COVID-19 pandemic

2021 (June 19) - 52 F low / 69 F high, cool & cloudy

2022 (June 18) - 47 F low / 63 F high, cool, clearing through the day

2023 (June 17)) - 50 F low / 77 F high, cool in the morning, warm in the afternoon