PROSSER, Wash. – It was a tale of two summers in central and eastern Washington. Following a cool June and July, August warmed up in central Washington, report Washington State University agricultural meteorologists Gerrit Hoogenboom and Nic Loyd.
“August was seasonally hot and dry in central Washington, as the region returned to a more typical late summer weather pattern featuring high temperatures generally in the upper 80s to lower 90s,” Loyd said. “In fact, daily high temperatures were up to 2.2 degrees above normal during August.”
The century mark was finally reached Aug. 26-27, with WSU AgWeatherNet’s Orondo station (north of Wenatchee) reporting 101.5 degrees on Aug. 27. Normally, August is slightly cooler than July – but not this year.  August was the warmest month of the year and indeed the warmest August in five years.
“It really was a tale of two summers,” Loyd said.
This summer, the U.S. experienced two separate temperature patterns, Loyd said. The Northwest received cool daytime weather in June and July while the central and eastern states received the opposite. In August, the central and eastern regions began to cool while the Northwest began to warm due to the lack of cooling influence from the Pacific weather systems, he said.
At the WSU Irrigated Agriculture Research and Extension Center in Prosser, where AgWeatherNet director Hoogenboom and Loyd are based, there were six consecutive months of below normal temperatures in the period ending in July, an unusual beginning for the Washington growing season.
For farmers, the news is mixed. Initial reports indicate that the 2011 Washington apple crop will be down a few percent compared to last year due to the cool and wet spring. By contrast, a 20 percent decrease in wine and juice grape production in 2011 has been observed due to damage received during the autumn freeze in November 2010.
Overall, despite a cool spring and an initially delayed growing season, the summer growing conditions have been excellent. Washington prune production is expected to increase in 2011, pear growers report good bloom, fruit set and quality, and peach growers report good fruit sizing and growth, thanks to the slow, cool growing season.
AgWeatherNet is an online service that provides raw weather data through the WSU weather network. AgWeatherNet is available online at