People that live in the Twin Ports region 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 55.5 degrees. The coldest marathon conditions on record were in 1991, where 39 degrees was record. 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