Speedplay Zero Hotspot

It's summertime, and your foot is hot. Probably doesn't have anything
to do with your pedal/shoe combo.

Happens to me every summer. I do fairly big miles every winter with
nary a complaint of hot foot, then come summer time my feet burn like
hell.

Much lower mileage, yet hot foot complaints. I've found that even if
my socks are too snug, I get hot foot. I'm more likely to get hot foot
in the evenings as opposed to in the mornings, due to the typical
slight swelling of the feet throughout the day and the higher temps in
the afternoon vs the morning.

So, I wear my shoes a bit looser (especially in the forefoot area),
wear looser socks, and don't have as much trouble.

If you find yourself out on a ride and the hot foot gets unbearable,
try taking your socks off. It'll probably help.