I was hoping/expecting there to be an amusing end to that video and watched all the way through in anticipation. Imagine my horror when I realisex it was genuinely that bad! You are an evil man Skeggy!
As for when summer starts, it depends on which method you choose to calcilate it, therd are several so there will always, corrdctly, be disagreement.
http://en.m.wikipedia.org/wiki/Summer
To be honest, other than night time temperatures, it feels like summer has arrived here already, spring was here at the start of April. I just hope the good weather continues into the traditional summer months.