If you're in a warmer climate you're getting more infrared, which provides most of the heat aswell.

Closer to body temperature means reducing the energy cost of keeping the body war. So more cellular energy for repair, cognition, and performance.

Also your your mitochondrial haplotype (maternal lineage of your mitochondria) may influence this too. Maybe your haplotype evolved in warmer climates and your mitochondria run more efficiently in heat and light.