Morning is usually 14km (but can be as short as 5km if I'm in a hurry, which is almost never).

Afternoon is usually 21km (but again, can be as short as 5km, and some days I'll do 30+km on my way home).

Flat both ways. I wear dedicated cycling clothes and change when I get to the office. With a towel off and deodorant even the hottest summer days aren't an issue.