SIOUX FALLS, S.D. (KELO) — It has been a hot day across KELOLAND and more heat is expected this weekend.

One tool could be helpful for understanding how stressful this heat can be to our bodies.

Levitt, other events impacted by heat this weekend

With the Summer Solstice on the way for Friday, it sure is going to feel like it across KELOLAND. Widespread 90s are expected, along with quite a few highs hitting triple digits.

You may have heard about the heat index, which is the feels like temperature. This is when relative humidity and air temperature are combined. But did you know that this is only calculated for shady areas? That means this tool may not be as helpful if you are spending time in the sun this weekend. Something else that would be better to look into is the Wet Bulb Globe Temperature. It considers more factors, along with direct sunlight.

There are multiple levels of Wet Bulb Globe Temperatures, from low to extreme. As you go up the scale, your chance of experiencing a heat-related illness increases quickly. The Wet Bulb Globe Temperature in southeastern KELOLAND will be in the high category from Friday through Sunday.

Other portions of central and eastern KELOLAND will climb into the high level by Saturday. This means that heat illness is possible within 20 minutes of being in the sun. To prevent this from happening, it is important to take a 40 minute break for every hour in the sun.

Those in the moderate levels, like western South Dakota, have an extra ten minutes before illness could strike.

By Friday morning, eastern and central KELOLAND will be included in heat warnings or advisories that will continue through Sunday.