Pic 1 - 5km, 16°C in the rain
Pic 2 - 16km, 25°C
Pic 3 - HR in 16°
Pic 4 - HR in 25°
Yes, I knew I'd be running for longer in one of these, but the effort was still near enough the same for the first 5km. The heat makes a HUGE difference, so don't be afraid to slow down