Wednesday, July 15, 2020
July 15, 2020

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High-temperature records outpace record-low marks

Climate group puts week’s Arctic blast in larger context


The frigid air that invaded the U.S. from the Arctic during the past week has tied or broken nearly 400 cold temperature records, including all-time November records, across a broad swath.

Yet over the long term, data shows that cold outbreaks of this severity are becoming a rarity, as record highs outpace record lows by an increasingly large margin. Nationwide, record highs have been outpacing record lows 2 to 1 this decade, whereas in a relatively static climate, one would expect that to come out about evenly over the long term.

The findings — according to NOAA temperature data analyzed and provided to The Washington Post by the climate research and journalism group Climate Central — are in line with what would be expected in a climate warming due to increasing levels of greenhouse gas emissions from burning fossil fuels, such as coal and oil, for energy.

In Chicago, the period from 2010 to Thursday also shows more record daily highs compared with record lows, when viewed as raw numbers or as a percentage. The disparity is 74 percent for record daily highs compared with 26 percent for record lows. The 1990 to 2000 period in Chicago had more daily record lows compared with record highs.

In Minneapolis, which is often significantly affected by Arctic outbreaks, record highs are beating out record lows, 92 percent to 8 percent, since 2010, NOAA/Climate Central data shows.

And in Houston, which was also affected by the current cold snap, the current decade has an 89 percent and 11 percent split between daily record highs and record lows, respectively, through Thursday.

Since 1970, winter cold streaks are lasting at least one day fewer in most of the 244 U.S. cities Climate Central analyzed, with an average reduction of nearly five days.

The analysis is backed up by the National Climate Assessment, which was released in 2018 and found that across the U.S., “heat waves have become more frequent … since the 1960s, while extreme cold temperatures and cold waves are less frequent.” It projected the trends to continue, with an increase in heat-related fatalities likely to outpace any decrease in cold weather fatalities.

New climate research published this week finds that, based on computer model projections, parts of the world may see their seasonal climate conditions “rapidly shift” away from historical conditions dating back to preindustrial times.