Jordan Relays; 3 Events How to conserve most engery, cold and raining forcast, race starts nighttime?

I have to run a mile in my first event. About two events after a 800, than two more a 400. How can i conserve the most energy between events, its suppose to be cold and rainy, and its around 7 at night. I run 1600m4:34//800m2:01//400m54.5//