What century are the weather sites getting there info from (Phoenix: area, cities)

[Beware_of_Dog]

I searched several sites this morning to compare annual temps of Phoenix area cities to some other places. Every single one I checked showed summer temp averages for phoenix vicinity as about 10 degrees cooler for summer monthly highes and at least that or more for night time lows. I can't ever remember seeing July/Aug lows at 75 degrees. 85-90 degrees is more like it.

And for July highs they all seem to like the 102 degree figure. I just wonder which century they are getting these figures from. Makes you wonder if you can trust their figures for any city.

[Ritchie_az]

Well, the temps are "averages"... usually 25 year averages. Some years are hotter, some years are colder. Some years have hotter summers and colder winters, and some have colder summers and hotter winters. Some days are hotter and some days are cooler. Each year is different, and to an extent it's cyclical.

Phoenix Average Monthly Temperatures - Phoenix Weather by Month - Hottest and Coldest Days in Phoenix
Average Weather for Phoenix, AZ - Temperature and Precipitation

[keninaz]

It's my understanding that it's a 30 year average that is used and it should be the last 30 years assuming it's updated once in awhile.
30 years is also the period that the weather service considers for a climate change.
I understand from others for example that we used to get a lot more snow that we do now in Prescott, but that was 40-50 years ago.
If you think about it deserts come and go over the history of the world.
WX patterns change for whatever reasons.
AZ was mostly underwater at one time as I understand it.

[Ponderosa]

Originally Posted by keninaz

It's my understanding that it's a 30 year average that is used and it should be the last 30 years assuming it's updated once in awhile.
30 years is also the period that the weather service considers for a climate change.
I understand from others for example that we used to get a lot more snow that we do now in Prescott, but that was 40-50 years ago.
If you think about it deserts come and go over the history of the world.
WX patterns change for whatever reasons.
AZ was mostly underwater at one time as I understand it.

LOL. It still is.