Smack dab in the middle of the heat wave, Friday posted some impressive yet stifling numbers. Aided by crystal clear, sunny skies and almost unheard of dew points in the lower to middle 80’s, we didn’t need to break record high temperatures to get some pretty crazy heat indices.
Max air temperatures were mostly in the lower to upper 90’s but the air didn’t need to warm up much as we did set a few records for the warmest low temperature. The new records came in Waterloo and Iowa City.
It is not very often that we see such a high heat index. In fact, we typically average less than 1 hour of heat indices 110 degrees or more per year.
What fueled such a high heat index was the downright tropical dew points in the 80’s. That doesn’t happen very often as the graph below shows we only see an 80 degree dew point about twice per year.