Summer 2014 hottest on record in central Washington

By Rachel Webber, College of Agricultural, Human & Natural Resource Sciences

AgWeatherNet-logo-120PROSSER, Wash. – It’s official. This summer’s heat set a record. And it followed the warmest spring in 20 years, which made the 2014 growing season an unusually prolonged period of anomalous warmth.

“2014 was Prosser’s hottest summer on record in terms of highs, lows and overall mean,” said AgWeatherNet meteorologist Nic Loyd. “In fact, nearly 12 years have passed since Prosser experienced such large positive temperature anomalies in any season.”

A Web-based, publicly available system, AgWeatherNet ( provides access to near real-time weather data and value-added products from Washington State University’s statewide weather network, along with decision aids for agricultural producers and other users.

The AgWeatherNet monitoring station in Pullman.

The summer ended with the hottest August on record in terms of the overall mean and mean low temperatures, while July 2014 was Prosser’s hottest month ever. In contrast to July and August, June was a relatively uneventful month.

With an El Niño event developing, above normal temperatures could be with us for some time to come.

“It was difficult for some growers to keep pace with irrigation demands and heat stress management during the relentless summer heat,” said Gerrit Hoogenboom, AgWeatherNet director. “Unfortunately, some peaches were splitting due to rapid growth associated with the extreme heat. However, most crops are reporting good quality and minimal negative effects from adverse hot weather conditions.”

July was consistently hot and featured two notable heat waves. The first, around mid month, was highlighted by a sultry low temperature of 84 degrees at Wahluke Slope on July 13 and then a high temperature at the Tri-Cities of 109 degrees on July 16. At month’s end, another hot spell sent temperatures soaring into the 100s across most areas east of the Cascades.

Unfortunately, the Carlton Complex fire was one result of the scorching weather; it burned more than 400 square miles to become the largest wildfire in state history. The only interruption to the hot and smoky July weather was a potent upper low that spawned some wet weather on July 23.

August began with sizzling temperatures. The Tri-Cities recorded five days at 100+ degrees Fahrenheit by July 11; that day, the heat peaked at 104.

Despite some slight relief around mid month, it was not until the end of August that more pleasant conditions arrived in Washington. The high temperature at Pullman was 69 degrees on the final day of the summer.

Although much of the month was dry, there were several stormy periods during which isolated, heavy rainfall was observed. One occurred Aug. 13-15. On Aug. 14, Boyd District received 1.5 inches of rainfall, which was followed by over an inch at Almira on Aug. 15.

Another active period later in the month brought 0.89 inches to Moxee on Aug. 24.


Nic Loyd, WSU AgWeatherNet meteorologist, 509-786-9357,