97 GT Gear Shifter sticking!!!

I have a 97 GT Auto, and during the cold times of the year my gear shifter sticks in park. This only happens when its cold outside and it sits for a long period of time. If I let the car warm up for about 15 minutes then it comes out of park fine. Is this some kind of safety thing or what! What should I do?
It has 90,000 miles on it. And it has done it since 50,000 miles!!

Thanks
Stang_girl20