Well I use 5w/30w synthetic motor oil in the winter, my 01 cavalier Ive got 155,600 km's, I also use 10w/30w in the summer. Seems to work great with no problems.
5w/w30 oil should work just for you.
Ok thanks man! (oh and just encase your wondering im not a n00b its just this is my first gm car everything else i have owned have been fords

)
My car--->
http://www.cardomain.com/ride/2569452
sae-30!! I use that on my 96 z with 149.xxx miles. I live in florida too tho... If its cold go with a thinner oil.
I also live in Florida also so i know what you mean. I am going to this car from a truck that had almost 500k miles thing was so worn out that it would not start if you did not put in 20-50 with a can of stp

.
My car--->
http://www.cardomain.com/ride/2569452