Remember that it was the Met Office that predicted it wrong last year, not Postive Weather Solutions.
Seasonal forecasting is not completely accurate and thus should not be taken too seriously. Any forecast beyond five days should be taken with a pinch of salt.
If I understand it correctly, while easterly winds across the UK
like we've had this winter produce cold weather, during the summer, when the land mass across Russia etc heats up, it can produce hot weather, should the winds blow our way.
The Azores high also plays a part, I think. But I'm not even a beginner. We need Rob