Two nights ago I did 6 x 1 mile in 5:35 average (slowest 5:37) on 1 minute rests on a very windy track in the dark at -2 Celsius. It wasn't an all-out workout and I think I could have done around 5:30 average at a push. I also think the wind probably took around 5s/mile out of me. I did this workout mid-week and had done 2.5 hours hard cycling the day before. Any ideas as to what I could run for 10k?