30 day means are calculated from daily minimum and maximums. The green line shows the year so far. It lags by 15 days from todays date because of the 30 day averaging.
Dashed red/blue lines are a curve fit to the Climate since 1961.
Note that daily minimum and maximums are computed from hourly temperatures which are under-sampled compared to the real temperatures - so the wiggly maximum curves should be a bit higher, and the wiggly minimum curves should be a bit lower.