Where have the butterflies gone?

This is the Buddleia in my garden which has loads of flowers on it. I’ve not seen one butterfly on it this year and, come to think of it, not seen very many at all this year. Has anyone else noticed that?
At the moment I’m watching my newly acquired Sky Sports HD channels! The 100 cricket is on which I turned my nose up at when it was first broadcast but I absolutely love it and am hooked on it now. It might not be to the purists taste but I love the excitement and speed of it.