(Radio Iowa) – Those thousands of bicyclists who will trek across Iowa next week will face many challenges, not the least of which will be Iowa’s summer heat. Meteorologist Kristy Carter, at the National Weather Service, says they’re predicting a heat wave to arrive right around the time the Register’s Annual Great Bike Ride Across Iowa begins on Sunday, meaning, those RAGBRAI riders will be roasting for much of the journey. “We still have the generally cooler conditions through the rest of this week, but we are looking at that warming trend starting next week with some actually pretty hot conditions by roughly mid next week, where our heat index values may reach or near at least 100 degrees,” Carter says. “We are certainly looking at that signal for above-normal temperatures.”

So far, this July hasn’t been as brutal as in summers past, but forecasters say that’s about to change. Carter says, “Right now, the official forecast only goes out through really next Wednesday, but we are looking at highs in the mid to upper 90s on both Tuesday and Wednesday.” Depending on the humidity levels, the weather service may be issuing heat advisories or even heat warnings next week. “That’ll certainly be something we’ll be watching over the next several days, just to see how everything plays out with what are the temperatures, what are those dew point values,” Carter says. “Right now, our heat indices are, for the most part, below 100 and our forecast for next week, that’ll certainly be something we’ll be watching.”

The experts say one key way to stay safe when it’s sweltering outdoors is to limit physical activity, which isn’t an option for those who are pedaling their way across the state. Carter says RAGBRAI riders should follow the rest of the guidelines. “Wear light-colored clothing, make sure to have plenty of water,” Carter says, “and just try to maybe bike a little bit earlier in the day, if possible, just to kind of avoid that late afternoon heat.”

The 50th annual ride starts Sunday in Sioux City and ends next Saturday, 500 miles later, in Davenport.