My Iphone 4s shows No Sim after being outside?

I went to play hockey at the outdoor rink with my iphone in my coat pocket and when i came back in to warm up i tried to use my phone and noticed it said "No SIM" where usually it says "ROGERS". I have never experienced this problem before and i want to know if its related to the cold weather and how I could fix this problem. I have tried powering on and off but with no luck.

It just popped out of place. It has happened to mine before too. Just take a pin or something sharp to pop it open and reinsert it. It's located on the side of your phone.