With temperatures hovering around 100 degrees outside, bicycling isn't high on most people's list of outdoor activities. However, there are strategies for riding relatively comfortably when it's hot.
Even on the hottest days, the temperature at 7 or 8 a.m. is relatively mild. Tomorrow at 7 a.m. the forecast temperature is 80 degrees, and 82 degrees at 8 a.m. Riding slow can reduce sweating, but sweating can be one of the factors that makes riding in hot weather bearable.
As sweat evaporates from the skin, the skin is cooled through the process known as evaportive cooling. The latent heat required to convert a liquid, sweat, to a vapor, causes the skin to feel cooler. Having a breeze helps, and we've always got a breeze while riding. This principle works great when the air is dry. There isn't as much cooling in our area with such high humidity, but there is some. Wearing light, synthetic fabrics that don't hold much water helps.
Over time, we learn how our body works. Riding at a slow pace so that we don't sweat a lot, but enough so that we're cooled. Taking in adequate water to replace the liquid lost as sweat is also important. Sport drinks can help replace minerals that are also lost.
It's always good to allow for a cool down period as you finish your ride. Without doing so, you'll continue to sweat after you stop riding. Slow your pace and take advantage of that evaporative cooling as you end your ride.
Just because it's hot doesn't mean you shoud stop riding. However, another factor to consider this time of year is air quality. When the Air Quality Forecast level is Red, consider using another means of travel such as taking the bus. Riding on a Code Orange day is questionable.
One advantage to riding when it's hot is that you have the trails mostly to yourself.