Cold weather camera use (-35 degrees C)

I’m off to Lapland next week. Is it worth taking my 5D Mk II?

Given that we have 4 hours to kill at Helsinki Airport we will be visiting the nearby aviation museum.

Northern lights, sleigh rides and family skiing seem the ideal opportunity for photos but I am thinking that as soon as I take the camera outside or bring it back inside it will fog up.

Day time temperature is likely to be -25 degrees with at least 10 to 15 degrees of wind chill.

Does anyone have knowledge they can share?

thanks

Tim