July’s Heat – A Rarity, But Not a Record

by Categorized: Data, Environment, Science Date:

The thermometer maxed out at a comparatively chilly 87 degrees in Hartford Sunday, meaning the region’s stifling, week-long heatwave is officially one for the history books.

But it’s not one for the record books.

cokethermometerBy almost every measure, Hartford has endured worse than the seven-day roasting that began with July 14th’s 92-degree day. Seven straight days of 90-degree weather is highly unusual for the region. But record-breaking? Not even close.

Including the heatwave that concluded Saturday, Hartford has recorded at least 10 week-long stretches of 90-plus temperatures since 1920 – the earliest year for which electronic data is available. And in six of those events, the hot weather extended at least to an eighth day, including – how quickly we forget – an eight-day stretch just two summers ago.

In 1973 and again in 2002, Hartford sweltered during nine-day stretches of 90-degree heat. And while data for much of 1995 is unavailable for Hartford, the weather station at Bradley International Airport recorded a ten-day stretch of 90-plus weather that year.

This recent heatwave began less than a week after a previous run of hot weather, a five-day stretch of temperatures topping 90 than began July 4th. That means there have been more 90-degree days than not this month, a rarity – but again, not a record.

So far there have been 12 days above 90 this month, but we’re not likely to add more than one or two additional super-hot days – and probably won’t add any – through the end of the month. So we’re certain to lag behind July 2010’s 16 days of 90-degree heat, and the 15 days in July of 2011 and 1999.

July 2013 does cling to one record, though it will be temporary. Through Sunday, the average daily high temperature for the month was 89.4 degrees. That’s higher than any July in the past 93 years for which data is available. But that top spot won’t last.

With moderating temperatures forecast for the rest of the month, July 2013 will likely end up as one of the five or ten hottest on record, but still less steamy than the Julys of 2010 and 2011. (And July 1999 will likely retain its title as the hottest month on record, with an average high of 89.2 degrees.)

While this particular blazing stretch may not medal in the heat Olympics, it does appear to be part of a larger trend of unparalleled high temperatures. Over the past 10 years, the average high temperature in July  – the hottest month of the year – was about 85.5 degrees, nearly a full degree higher than the next-hottest 10-year stretch going back eight decades.

And that’s a record that could well leave those concerned about global warming breaking out in a sweat.

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5 thoughts on “July’s Heat – A Rarity, But Not a Record

  1. Joanie W.

    The difference with this one was the night time temperatures, which almost never got below 80. That has never happened before

  2. ignoreland

    Climate change is not only about temperature, but the entire picture is still not being presented in the article:
    As mentioned in the comments, nighttime “low” temperatures have been consistently above average throughout July, 2013. Through July 22, nighttime lows average 71.2 degrees at Bradley airport, at least eight degrees above July’s established normal. (Plus if you are like many human beings it’s difficult to ignore this month’s consistently high dew point readings, also.)

    Yes, we will find out where this exceptionally warm July winds up in the record books. Through July 22nd, the daily average temperature (at Bradley) is 80.5 degrees. The current average temperature record for July (and any month) here is 77.1, last set just three years ago.

    Gonna need to cool down – including at night – to avoid being the hottest month on record in hot-July’s Hartford…

  3. Outhouseguy

    Don’t matter if you hit a record on each count. Afterall a NASCAR driver can still take the championship without winning a single race. Same with weather stats.


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