While waterproof leather boots are ideal in cold, wet weather, ventilation and breathability count the most in warm weather. Opt for boots that incorporate mesh in their construction, feature ventilation panels on their sides to enhance airflow and include a liner made of breathable fabric.
The boots should fit over your ankles and include a nonslip sole. Underneath, wear a pair of socks made from a blend of synthetic, sweat-wicking fibers. Like your base layer, the socks will draw out moisture and cool your feet down. And even on the hottest days, never wear sneakers -- they offer little protection in the event of a crash.