The definition of 'normal weather' across the US is about to change, according to new figures from the agency that publishes climate data that also show it is getting steadily hotter.
Each decade, the National Climate Data Centre, which is part of the National Oceanic and Atmospheric Administration, updates a set of weather data known as the 'normals'. This data averages temperature and precipitation over a thirty-year period to help businesses predict weather trends. For example, utilities use it to predict electricity sales, and it is also useful for the agricultural industry and other commercial sectors.
This year, the NCDC will drop the 1970s from its data set, and will replace it with data from the last decade. According to staff responsible for the project, losing the 1970s data will increase the average temperature. For example, according to a report published this month in Scientific American average temperatures in the upper-midwest will increase by 1-2.5 degrees farenheit (0.6-1.4 degrees celsius).
In contrast, the southern central part of the country will cool by around half a degree, while the US can also expect to see a slight drying of the west, which could
have worrying results given the drought that the south-west has experienced over
the past few years.
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