@bovidae yeah same as most places, bit daft really, I know the Whangarei Airport is often 6 or 7 degrees lower than in town.
Tuesday last week the 'official' temp was 26, but I was at a Funeral at Toll Stadium and the temp there was 35, my car told me it was 37 (which is usually about 2-3 deg higher than actual)
I expect the idiots that designed our flash bridge used that sort of data and the variance was only to about 25deg and then first summer it was complete, it wouldnt work as the metal expanded too much at 25deg.