Starting Saturday our temperatures will be a good bit warmer with highs in the mid 80s around Duluth and near the lake and near 90 away from the lake. Add to this the humidity with dew points expected to be in the low to mid 70s and you have potential for heat related illnesses. It's going to feel like a big shock, especially after the past 3-4 days we've had with low dew points and cooler than average temperatures!
The humidity will keep you from cooling off so much because not as much evaporation can occur because the air is already so saturated. With the humidity and heat we also see the potential for storms, each day. As of now Saturday through Thursday look to be hot and humid. Check on the elderly and people prone to heat related illnesses.
The best thing to do is drink plenty of fluid before you go out into the heat and also drink non-alcoholic and non-caffeinated beverages during exertion outdoors in the heat. Light and loose clothing is also best!