Originally Posted by pedigree 6
I was just wondering if anyone here is able to answer this?
When we say above or below average temperatures, rainfall, any weather, etc.
How is the average worked out and how many years does it go back to, to work out the average?
Is it always since records began or maybe the last 20 or 30 years?
Thanks in advance.
The average is based on a certain 30 year average. The most recent average we use is the 1981-2010 average. Before that, we used the 1971-2000 average and before that, the 1961-1990 average etc. So the next 30 year average will be 1991-2020.
Of course, not all stations do it this way. For example, my station Grange (just as an example) uses the 1986-2016 average because my station's records go back to only 1986.
These are Ireland's average temperatures for each month (1981-2010 average) (in case anybody finds these useful for any calculations):
August: 15.3 (Yes, August 0.1c hotter than July