Summer here we come?

On the morning dog-walk, on this last day of May, I'm wondering if we're really ready for summer, and can the longest day only be a few weeks away? We don't seem to have had much of a spring.
Then later I read in the paper that the average temperature March to May is set to be the third highest since records began just over a hundred years ago. Really?
Of course the trees aren't worried about such debates. All they know is this is the best opportunity to put on new growth, so better get on with it.