Is it really Spring?

It has been a somewhat uncertain Spring. At first we thought it would be an early growing season, but now that doesn't seem to be happening. It's late enough to plant broccoli, cabbage, celery, Brussels spouts and cauliflower outside, but we are waiting until the threat of hard frosts are done. Even cold weather plants usually grow really slow when it's cold, so you don't gain much growing time by planting when its too cold.
We always wait until mid-May to plant beans and squash seeds outside and we wait until the end of May to plant egg plant, peppers and tomato plants.