Can I Get Away With Using Interior Paint on the Outside of an Exterior Door?

Title is pretty self explanatory.

Doors are wood and varnished, I sanded the varnish slightly to make it more abrasive, and will prime it. I have white interior paint which will be used to paint the inside of the door... should I also paint the outside of the door with the same paint, or is it really recommendable to do buy a pint of exterior paint of the same colour to paint the outside?

I've read indoor paint resists less well to the sun and the color would fade sooner, but it's white so it can't fade.

Also, I live in Canada and it gets cold as hell, if this changes anything.

Thanks
Nic

 

I'm not overly familiar with how paints react to the extreme cold but the main drawbacks to using interior paint on the exterior are; it will peel sooner, fading and it's more apt to mildew - the first two are a direct result of the sun exposure. White paint might not fade but it will still deteriorate.

If the door is protected by a storm door the interior paint has a fighting chance but if it was me - I'd use exterior paint!

 

Thanks!
I'll just go ahead and do that
Nic