I just finished a 6.187km running that lasted about 0hh:35mm:54ss !
It's getting colder and darker, so when it comes to speed work, you can either go to the gym or you can head to the track.
Although, its dimly lit, it is still lit up a little. You also know the track is pretty flat with no pot holes. It's not bad at all and a nice change to getting to the gym. Tonight was 10 minutes warmup, 20 minutes of 100m slow running, 100m medium running, followed by 200m of fast pace running.
It's a session that can be as tough as you want to make it.