The temperature anomaly graphs below show the difference between the annual average temperature in Portland, according to NOAA, and the average annual temperature in Portland in two 30-year base periods. The first graph uses 1981-2010 as the base, the second one uses 1951-1980. I include the first graph because NOAA currently uses 1981-2010 as the basis for climate and that is the basis for normal temperatures generally referenced in this blog. The graph using 1951-1980 is more useful because it shows the rapid warming since 1980 more clearly. The last year with temperatures below the 1951-1980 average was 1978; the last 36 years have all been at or above the 1951-1980 average! The third graph shows rolling 10-year average anomalies, which have been on the rise since the decade ending 1967. I'll compare these trends to worldwide temperatures once the 2014 averages are published by NOAA.
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SOURCEWeather statistics are based on 5-minute readings at an Ambient Weather station near Mill Cove off of upper Harpswell Sound. Archives
December 2015
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