It is well-known that the contiguous US (CONUS) is by areal average much hotter than England and Wales in the northern summer, and colder in the winter. What I will try to do here is see how much variation there is between these normals, since the annual temperature means overlap somewhat. Since the CONUS averages a little hotter than England and Wales over the whole year, I will take positive as meaning the CONUS is hotter, negative that the CONUS is cooler than England and Wales.
Data exist for the years from 1895 to 2014, and I will do figures for fiscal year (July to June) as well as temperature. Fiscal year should provide a better picture than calendar year due to the greater influence of winter temperatures an annual variation, avoiding situations where unusually cold or warm winters are divided between two years.
|Month||# CONUS hotter||# CONUS cooler||Year of “highest” departure||Year of “lowest” departure|
It can be observed that some extremes, noted in red above, seem to be systematically influenced by man-made greenhouse gas emissions.
Although I could use an earlier date since rainfall records in the southern hemisphere indicate man-made global warming (countered in the northern hemisphere by short-lived aerosol pollution) was taking control of the climate as early as 1967, I will use the 1980 Lonie Report – which paved the way for major expansion of polluting freeways in by far the planet’s worst greenhouse polluter (Australia) – as a cut-off for “natural” variability. Previous records for those established since are:
- July “lowest”: 1976 (CONUS averaged 72.90˚F or 22.72˚C; CET was 18.7˚C or 65.66˚F)
- August “lowest”: 1975 (CONUS averaged 71.53˚F or 21.96˚C; CET was 18.7˚C or 65.66˚F)
- September “lowest”: 1949 (CONUS averaged 63.73˚F or 17.63˚C; CET was 16.3˚C or 61.34˚F)
- April “lowest”: 1944 (CONUS averaged 48.97˚F or 9.43˚C; CET was 10.2˚C or 50.36˚F)
- December “highest”: 1933 (CONUS averaged 36.43˚F or 2.46˚C; CET was 1.3˚C or 34.88˚F – though Scotland was actually milder than England or the CONUS)
- April “highest”: 1908 (CONUS averaged 52.75˚F or 11.53˚C; CET was 6.0˚C or 42.8˚F)
- February “highest”: 1954 (CONUS averaged a record 41.11˚F or 5.06˚C; CET was 2.6˚C or 36.68˚F)
|Temperature for the winter of 1916/1917. Note the uniform cold over most of the northern hemisphere apart from the subtropics, Central Asia, Greenland and Sakhalin.|
|Temperature anomalies for May 1917. Note the extreme and uniform cool over North America, Australia, East Asia and and eastern Europe|
|Rankings for May 1917 in the contiguous US. With over 87 percent in the “very cool” category this month is by mean temperature percentile by far the coolest from coast to coast.|
Dorrigo Post Office a daily fall of 774.7 millimetres (30.50 inches) is generally regarded as an NSW record. The Macleay River was thirty feet (nine metres) deep as it raced through Kempsey.
|Rainfall over Australia, February 1954. Note the extreme dryness over WA, where essentially no rain fell south of the Kimberley – then affected by a four-year drought of a type unknown to its present inhabitants.|
|This animation shows US temperatures during the hot and dry English summers of 1975 and 1976. It was notably cool in the West and South, where 1976 is the coolest calendar year since records begin.|
|Contiguous US temperatures for the summer of 1954. Note the unusual cool (and rain) over the Pacific Northwest and heat (and drought) over the Southern Plains|
|Global temperature anomalies for April 1944. Note the cool over Australia, Beringia and the central US, plus the heat over Western Europe that made Britain hotter than the CONUS.|
September and October 1931 were very hot over the interior US – the end of the great drought of 1930-1931 as November saw big rains:
|The hot September and October of 1931 over the US – it’s a pity the colour was lost when I formed an animation!|