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I noticed American and Canadian cities use the 1981-2010 normals (at least on Wiki), though Australian cities use the more historic ones that date to the late 1800s and early 1900s (when they first began, if you want).
Should we switch to the 1981-2010 normals or are the more historic records more accurate representations of a city's climate?
I'd imagine the modern normals are more accurate for Australia - a lot of cities are averaging something like 1C higher than the historic averages in the past decade or so.
I'd imagine the modern normals are more accurate for Australia - a lot of cities are averaging something like 1C higher than the historic averages in the past decade or so.
Quote:
Originally Posted by DesertSun88
1981-2010 is by far more accurate for Australia. Seems to be the norm for America as well on their Wiki climate tables.
Yes. Notice the difference between the 1881-1910 and 1981-2010 normals of Sydney - A rather resounding difference in a 100 year timeframe:
It's like Sydney changed climate zones - from Oceanic to Humid Subtropical in less than a century.
This looks wrong to me - is it possible the older temp range have a lot of missing data coded as zeroes that are getting picked up and averaged in? That would explain the lower temps...or perhaps unreliable measurement methods from that time period?
I never liked the "30 yr" normal that we do. Since the 1970s were eliminated the normal went warmer of course. I always thought 30yrs was not enough to capture the climate normal. Would think 50yrs at least is better but I understand why they do just 30 I guess. And it changes every 10yrs too so the next "normal" will be 1991-2020.
The changes in those winter highs are quite something- from temperate to subtropical. Sydney's former winters are about the same as Auckland's today. The earlier period seemed to have a more seasonal rainfall pattern too, with a defined wet season in autumn and early winter.
1981-2010 is obviously more relevant for us today, but these older records are invaluable for comparing things.
In my personal records I compare all data to the 1981-2010 average.
I once found some records for Buxton for the period 1920-1959 and it was a lot colder then. Average highs were 63°F for august and 40°F for January. Nowadays it's 65.3°F and 41.4°F respectively and also with much milder lows.
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