Summer 2009/2010 starts

I have a algorithm for detecting summer. Seven consecutive days in a row with a temperature of or above 20 degrees Celsius. I give you Summer, from the Bureau’s seven day forecast for Melbourne:
Forecast for Monday Max 20
Forecast for Tuesday Min 8 Max 24
Forecast for Wednesday Min 10 Max 25
Forecast for Thursday Min 12 Max 28
Forecast for Friday Min 16 Max 29
Forecast for Saturday Min 18 Max 28
Forecast for Sunday Min 16 Max 26
I should also point out that I consider there to be two seasons in Melbourne: Nice-but-hot (summer-ish) and a-bit-iffy (winter-ish).