Weatherproofing

Making a keypad to mount on the outer wall of the garage requires some weatherproofing. First I had to add a capacitor to overcome the voltage drop over the 2 meter long lead, and add quite large pull-downs (15KΩ). Now I need to make the whole shebang work in -20˙c, and even in blizzards. This has prooven to be harder than I thought. The relay won't work when it's cold, even though it rated to work just fine down to -40˙c. I'll try to solve it with more power, regulated from a transistor on the out-pin of my controller.

Any tips on outdoor electronics are welcome in the comments!