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July was the Hottest Month on Record in California, Record-Wettest in Mid-Atlantic
Published: August 8, 2018
California experienced its hottest single month in 124 years of recordkeeping, according to NOAA’s monthly summary of United States climate released Wednesday. For the contiguous U.S. as a whole, it was the 11th-hottest July on record, with almost every state coming in warmer than average. The national average of 75.5 degrees Fahrenheit was 1.9 degrees above the 20th-century norm, said NOAA.
California’s average for July of 79.7 was 0.2 degrees above the state’s previous hottest month on record, July 1931.
In addition, several communities in California and adjacent Nevada had their all-time hottest single month. These include:
- Palm Springs, California: 97.4 degrees (previous: 97.2 in July 2006)
- Fresno, California: 88.2 degrees (previous: 87.8 in July 2006)
- Bishop, California: 81.8 degrees (previous: 80.8 in July 2017)
- Reno, Nevada: 81.8 degrees (previous: 80.5 in July 2017 and July 2014)
- Tonopah, Nevada: 79.7 degrees (previous: 78.9 in July 2017)
- Winnemucca, Nevada: 78.1 degrees (previous: 77.5 in July 2014)
- Elko, Nevada: 77.2 degrees (previous: 76.8 in July 2013)
- Blue Canyon, California: 74.2 degrees (previous: 73.7 in August 2012)
Most notably, Death Valley recorded an astounding monthly average in July of 108.1 degrees. This is the highest monthly average on record for any station in the world, based on the global archives maintained by NOAA’s National Centers for Environmental Information (NCEI).
The blazing temperatures in California, combined with the normally parched summer climate, helped to stoke wildfires that are continuing to ravage the state. These include the Mendocino Complex, the state’s largest fire on record and the first to top 300,000 acres.
Eight states across the West had a top-10-hottest July, including California.
The nation’s other hot pocket was New York and New England, where each state had a top-10-hottest July. Both Caribou, Maine, and Burlington, Vermont, saw their warmest average on record for July and for any other month. In Caribou, the July average of 70.9 degrees was the first time any month has topped 70 in records going back to 1939. The 76.0 degrees in Burlington exceeded all months going back to 1892.
The latter half of July was very moist across the Eastern Seaboard thanks to a persistent upper low over the Ohio Valley and Appalachians – quite unusual for midsummer – that kept moisture streaming across the mid-Atlantic. Pennsylvania saw its wettest July on record, with a statewide average of 7.37 inches beating out 7.14 inches from 1992. It was the second-wettest July in Maryland records: the state’s 8.73-inch average was more than 0.90 inches above all other July totals, topped only by an amazing 10.70 inches from 1945.
Baltimore had its wettest July in 148 years of recordkeeping. The city received 16.73 inches, more than 5 inches above its previous record from July 1889. The only wetter month in Baltimore history was August 1955, when two hurricanes passed nearby.
Washington D.C. ended up with its fourth-wettest July on record through a strange juxtaposition, as reported by Capital Weather Gang. The first half of the month was record-dry with no measurable rain; the second half of July was the wettest on record.
Dry conditions held firm across the West, including the Northwest. Idaho saw its sixth-driest July on record, and Seattle picked up just 0.05 inches of rain compared to its long-term July average of 0.70 inches. Unless a major pattern change occurs, the widespread Western dryness will leave the region vulnerable to wildfire for weeks to come. In its Aug. 1 outlook, the National Interagency Fire Center projected above-average wildland fire potential in August for most of California, Oregon, Washington and Idaho.
The Heat Continues to Accumulate in 2018
Boosted by the extreme warmth of May, the last three months have been the warmest May-to-July stretch in U.S. weather history, with an average of 70.9 degrees topping the 70.6 observed in 1934.
For the year so far (the period from January through July), 2018 is the eleventh warmest year on record for the contiguous U.S. This is the warmest January-to-July in more than a century of recordkeeping for both Arizona and New Mexico, and it’s among the five warmest in California, Nevada, Utah and Colorado.
Pennsylvania experienced its wettest January-to-July on record, and Maryland had its second-wettest, as did West Virginia. The year to date has been wetter than average over a broad swath from Wyoming and Montana eastward across the Corn Belt and Ohio Valley into the mid-Atlantic, as well as for the lower Mississippi Valley and Florida.
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