Is every year averaged in?? I mean if it rained, abnormally, a lot last year, then wouldn't that effect the averages for the coming year in a false way?? The same goes , vice versa, for if the rainfall was, abnormally, poor in the last year. I may have not worded this too good, but that just goes to show how much I know on rainfall averages. Sure, I could have gone through a search engine and probably found the answer but I wanted to ask it here so as to be educational for anyone who reads the answers.
2007-03-20 02:15:42 · 4 answers · asked by Wayne 3 in Science & Mathematics ➔ Weather
Usually it is figured as the average over 30 years or more. That way, any one particular year has only 1/30 effect on the average.
2007-03-20 02:27:38 · answer #1 · answered by morningfoxnorth 6 · 1⤊ 0⤋
Well, it may still be they just set up rain guages
like back in the '70s. Every 24 they would bring
in the guage from outside, where the guage was
placed so it wasn't underneath tree branches,
or other things. Then the amount is recorded
everyday, and the amounts are all averaged
to get an amount. It might be in Surrey
and nowadays, the average would be in metric.
Sounds really simple, and the larger an area is
you use more guages. But that was a long time
ago.
..
2007-03-20 14:57:50 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Like any running average each year is added in for the annual contribution. And you are correct - some of these years may be out in the wings of the normal distribution, which we would expect if precipitation is normally distributed.
2007-03-20 11:57:03 · answer #3 · answered by 1ofSelby's 6 · 1⤊ 0⤋
They measure the rain for a while and then add it and then divide then they get a aversge rain fall!
2007-03-20 19:07:39 · answer #4 · answered by Rs 2 · 0⤊ 0⤋