Buy the 2015 Old Farmer's Almanac!
Actually..the most accurateActually..the most accurate thing I found is watching the mesquite bushes (I'm from west Texas) once you see them bloom, its more frosts have ever came past that point.

2015 Special Edition Garden GuideCooking Fresh with The Old Farmer's AlmanacThe Almanac Monthly Digital MagazineWhat the heck is a Garden Hod?