30 day averages are calculated using approximate minimum and maximum daily
temperatures. The green line shows the year so far. It is lagged by 15
days from todays date because of the 30 day averaging.
Note that the daily minimum and maximum estimates are all under-sampled compared to the BoM climate data and the real
temperatures, so all the wiggly 30 day average maximum curves should really
be a bit higher and all the 30 day average minimum curves should be a bit lower.