New Widget Tracks Record-Breaking High Temperatures


On July 22, thermometers in Newark, N.J., peaked at a staggering 108 degrees, the highest temperature ever recorded in that region. Days later on July 27, Joplin, Mo., broke a 60-year-old record at 105 degrees, scorching an area already recovering from spring’s deadly tornadoes.

Across the United States, extreme heat has claimed the lives of at least 60 people, the National Weather Service reported on Tuesday. With excessive heat warnings, unrelenting humidity and countless cases of heat-related illness nationwide, the weather no doubt feels worse than ever in large swaths of the country. But is it historically hot? That depends on how you define “hot.”

This year, the National Weather Service recalculated so-called normal temperatures across the United States, revising the average upwards by roughly half a degree to create a “new normal.” The uptick was based on 30 years of temperature monitoring.

Using data collected by the NOAA’s National Climatic Data Center, the PBS NewsHour has set out to track the number of high temperature records set each day of the year across the United States. We’ve built this widget so our viewers can understand the significance of the heat, not only in terms of raw degrees, but in a format that compares today’s temperatures to previous record highs. The widget is built to be embedded into any website, and the data behind it will be updated every day.

But what value is a total count of record-breaking temperatures? To help answer that question we compiled this chart of total records tied or broken each year since 2000, using the same methodology as our widget. According to this data, more records (5,420) were broken in 2007 than in any other year of the past decade. But 2011 is closing in, and may soon hold the record-setting record. Also, keep in mind that some records set in 2007 were broken in later years by even-hotter temperatures.

There are some important notes that we should outline about our methodology. The NCDC collects and records temperature data from official recording stations, as well as from trusted volunteer stations across the nation. Based on the advice of the NCDC, we are only counting temperatures recorded at official stations. In order to make it into our count, a recorded temperature must either tie or exceed a previously recorded temperature on that date in a previous year. NCDC records go back for many stations as far as the mid-19th century. (The oldest weather station in the United States, located in Manhattan’s Central Park, recorded a record on July 22 of 104 degrees.) Some weather stations do not submit their temperature data immediately, so counts for previous day’s records may sometime be revised upwards.

While extreme temperatures are most notable during a heat wave, records are set or tied year round, so this widget will run throughout all four seasons.

View All Temperature Records

Justin Myers, Vanessa Dennis and Jenny Marder contributed to this report.

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