Wildlife shooting

My photography class is scheduled to go to the zoo this Sunday to shoot some wildlife from 9am till 12:30pm. And that will also be part of my final assignment which is due in less than 3 weeks. But with the freezing cold that we've been having for the past couple of days, I'm not sure if I can stand being outdoors to do the wildlife shooting. It's in the -20sC right now and we might also get some snow this weekend. I don't want to miss the field trip as I don't want to miss all the tips and tricks that I could learn from our instructor. What should I do???

This is the one time that I wish the chinook would come in and warm up the place for our zoo trip. I honestly don't know what I am doing in a very cold country when I prefer the tropical weather.