I live right below Michigan....whether here hits both extremes; below 0 in the winter and over 100 in the summer. My '88 Bonneville made it to 185k before the ****** started to go (only problem I ever had with it), my g/f Explorer was ~190k before it's ****** started to go (again, only major problem with it), and my '86 LeSabre was over 150k and I never had any problems with it (other than that car that blew up next to it).
Honestly, you should be fine.
And if you want a new car, that's fine. Just remember; if you spend $15k on a new car you are basically throwing $7.5k out the window for no good reason. And other than mileage, $15k will get you a better used car than what you could get for $15k new (IMO)