Predicting the weather remains both science and art, but there are maps with projected spring and fall freeze dates provided by the National Climatic Data Center and the National Environmental Satellite, Data, and Information Service. These maps provided ball-park dates at two-week intervals. Certainly not precise, but for those new to gardening, they can help in planning when to start seeds or safely transplant tender plants.
Tool or Gardening Product
One of the biggest boons to starting seeds indoors is the bottom heat provided by a heat mat, sometimes also called a propagation mat. These plastic mats with heating tape embedded in them provide a safe, reliable heat source, as opposed to using a heating pad intended for human use. They are widely available at garden centers or through mail-order seed catalogs in sizes ranging from 22x14 inches to 22x96 inches (to fit standard-sized seed-starting trays). If you're detail-oriented, add a thermostatic control.