You are absolutely right. Unless your soil is mostly sand, tilling or working it when it is wet turns it into a sticky mess. In any season, wait until the soil dries enough to pass the squeeze test. Take up a handful and squeeze it. If it forms a tight ball, it's too wet. Ideally, it should be slightly more crumbly than cookie dough. It's perfectly OK to delay planting of tomatoes, peppers, beans, and other plants that like warm weather. However, if you wait until days become long and warm to plant cool-season crops such as lettuce, spinach, or peas, their flavor suffers and they quickly go to seed. Prepare the soil in raised beds in fall and cover them with polyethylene film through the winter to make sure you get an early start on the spring planting season. The film will keep excess moisture off the soil as well as warm the bed earlier in spring.