what would it take to get lake superior surface temps 70-80 degress many days of of 90+ and warm rains ?

also whats the warmest lake superior has ever got i know thats there been surface temps of 60-65 many times did it ever reach 70

To get the entire lake surface temp to 80 would take weeks of air temps in the 80's and 90's and lows in the 70's. Nightime temps have as much to do with lake temps as do daytime as there are almost as many nightime hours as daytime hours.

The lake can and does hit 70 in the far SW (near Ashland and the Apostle Islands) many times. However, mid lake temps typically to out in the upper 50's.

-John

The surface temperature of the Big Lake gets to 70 degrees even around the Keweenaw. There are several very sunny days where some of the shallower bays with a dark rock bottom heat up extremely fast. Especially along the shoreline from Eagle Harbor to Copper Harbor. I have already been diving and could feel the heat radiating off of the rock bottom thru my 6.5 mm neoprene gloves. Even in Copper Harbor I have read temperatures around 70 degrees on my dive computer. Now, obviously you don't have to get very deep and the temperature drops drastically. Underwater currents also play a big role in the temperature.

im talking about if the whole surface of lake superior was 70 degress. ive been in 70 degree surface temps before in the big lake also some inland lakes in keweenaw have almost hit 80