WENATCHEE — The National Weather Service in Spokane has gotten the question a lot this summer: Does it feel cooler than normal?
“We had that around Labor Day a lot too, a lot of people wanted info from us about it,” said meteorologist Laurie Nisbet.
And, looking at the data, it’s true — average temperatures in most of Eastern Washington, including Wenatchee, were lower this summer than the past few years.
The Wenatchee World analyzed more than a decade of weather records and found Wenatchee’s average daily temperature this summer was 72.27 degrees, the lowest figure since 2011.
The data is collected at Pangborn Memorial Airport’s weather station by the National Oceanic and Atmospheric Administration. It includes hourly, daily and monthly totals for dozens of weather variables.
It offers unique insight into a decade of Wenatchee weather. The hottest day was June 28, 2015, when it hit 109 degrees. The coldest summer day was June 7, 2012, when the temperature got down to 43 degrees at night.
But to understand the story of Wenatchee’s climate, the weather needs to be analyzed on a larger scale, said Assistant State Climatologist Karin Bumbaco.
“Our last few summers have been really, especially warm and dry, so it kind of made this one seem cool,” she said. “But when you compare to average, just looking at June, July and August, temperatures are pretty much near normal for the Wenatchee area.”
And when compared to a 30-year average, the summer of 2019 was actually 0.84 degrees hotter than normal, according to the data analysis.
“There really has been a difference this summer,” she said. “It’s almost like normal seems abnormal because the last few years have been so extreme.”
And when it comes to weather comparisons, context is key, Bumbaco said. That’s why most climatologists use at least a 30-year period when analyzing long-term weather.
“That (time period) just allows the thermal variations to even out and you can see climate,” she said. “But I think it’s just a constant battle in terms of recognizing that even in a warming world, we can still have very, very cold days and months.”
The State Climatologist’s Office, which operates out of the University of Washington, often has to look at even wider time periods when predicting droughts and other long-term climate patterns, Bumbaco said.
So it built a temperature and precipitation analysis tool that tracks trends across the state dating back more than a century. The tool is available to the public and has become one of the most popular features on its website, she said.
“It’s one of the questions we get all the time: ‘How are temperatures changing in our backyard? How is precipitation changing in our backyard?’” she said. “Everyone experiences weather, it’s the small talk when you run into people day to day. It’s a big part of people’s lives. Then to check to see ‘Are my perceptions accurate with data?’ I think people find it interesting as it’s something they experience day to day.”
Looking at 120 years of Wenatchee weather, the trend is clear — Temperatures are going up. The average day in 2019 is 2.34 degrees hotter than it was in 1894, according to the tool.
In that same time period, the daily low temperature has risen even faster, Bumbaco said.
“If you look at our longer temperature trends, we tend to see a greater warming trend in our minimum temperatures, so our overnight temperatures are warming faster than our daytime temperatures on the long term,” she said.
That’s the important part of comparing weather across years, decades or centuries, Bumbaco said. The summer of 2019 is cool compared to the last 10 years, but hotter than the 30- or 100-year trends.
“We as humans have very short memory of weather, we often forget,” she said. “We always think what we’re experiencing is the wettest or the driest or the hottest or the coldest. This puts it in the historical context to see how it’s changing.”