i need help

hello to all..as u may notice i'm pretty new to this forum..but i need your advice on the problem i have with my car..it's an 89 grand prix 2.8 engine..with auto tranny..when it's cold outside..the tranny doesn't want to shift into second gear..so i'm stuck to drive around 5-10 min in first gear obviously not going very fast...as soon as it warms up ( i guess) it shifts perfectly fine..i checked the fluid level ...it's been changed not too long ago and it's at max level...do u have nay ideas suggestions? or of how to warm up my tranny?..i always warm up my engine in the morning..or whenever the car sat for a long period..i must say here in canada the temperature is pretty low overnight in winter times..last night -27 Celsius..i'm waiting for your ideas..thx in advance..