Gardening is much more that planting a seed. The first item you need to know is what zone you live in. Spring it the time for planting but how do you know when to plant. How will the summer heat impact your garden productivity. How much rain can we expect in our area. When will the freezing temperatures start in the fall. What grows well in your area. What dose not.
These questions can easily be answered by averaging the climate of where you located over a number of years. This is what the USDA hardiness zone map has done for us. Learn you zone and find a wealth of information to help you garden throughout the year. Yes, the weather has changed over the last twenty years and the maps have been undated.