If Rascal were in your dog's position he would pee on the floor, too. He's pretty well housebroken, but he HATES going outside in bad weather. HATES HATES HATES it. So unless I force him to go outside he just won't do it, sweaters or booties and all.
The great news is that potty training in bad weather is really easy!!! The dog is super motivated to go inside where it's warm and cozy, so as soon as she realizes that she had to do her business in order to be allowed back inside, I bet you'll find she'll do it right away. In the winter, Rascal becomes a master of the "leap out the door and start peeing immediately" technique during the winter (watch your feet! lol).
The key is, as Callie said, you have to monitor her 100% of the time. She is motivated to pee where it's comfy - you have to make that impossible and take her outside frequently and then not back down. If you know she has to go, she is *not* allowed back inside until she produces something! (With Rascal at least this routine can take at least 15 minutes when the weather's nice and there are things to sniff. In the winter, a "long" wait is a couple of minutes.)
Is she crate trained? Confining her to a crate when you can't watch her would probably be very helpful.
Also, welcome to the boards :)