One big difference between this week and the July heat wave is the humidity. The dew point has been particularly low. In case you're wondering, the dew point temperature is the point at which the air must be cooled in order for the air mass to become saturated. I learned that in seventh grade science class where we would wet a wick on the end of a thermometer to get the dew point reading. The drier the air the greater the evaporative cooling and the lower the dew point. Conversely, when the air temperature is close to the dew point, the relative humidity is high - or something like that. I’m not Dr. Science but he does live in Iowa City, or at least he used to.
Anyway, by now you’re probably wondering where this is going. Well, many years ago while riding in the Utah desert, another cycling tourer showed me a clever way to keep your water bottle cool. Just put a sock on it. More specifically, put a wet sock on it.
While this technique is usually limited to very dry climates, this past week it worked in the typically humid Midwest. I won’t suggest the best sock material for this application. It does require you have a second water bottle to keep the sock wet. Currently, I have a mostly wool sock on my stainless steel bottle. The sock, I might add, also keeps the stainless bottle from clanging around in the cage.
I'm sure this is old news to a many riders, but if you've never tried it and the temperatures are high and the dew points low, give it a whirl.