Check out this graphic from the Washington Post that explains how your body acclimatizes to the heat of summer. Here in the American mid-South, we’ve been going through a bit of a late-spring heat wave, and I can tell you from personal experience that trying to ride or race through this kind of weather feels just brutal - and can even be dangerous. It will take two weeks or longer to adapt to full-on summer heat, and until then you need to be extra careful not to fall victim to heat illness such as heat exhaustion or heat stroke. Of course, even once you’re acclimatized, vigilance is required. Stay hydrated, but remember that drinking enough water doesn’t immunize you against heat exhaustion. If you experience unusual fatigue or dizziness stop immediately and get yourself out of the sun!