Meteorological summer (June through August) is over and that means we have lots of fun new data to pour through! This summer ended up being a mixed bag. We didn’t experience as extreme of heat as usual, but our mean temperature was somewhat above average. Interestingly, we were below average for precipitation.
Let’s start off by digging into the numbers. For this, we’re looking at what we experienced this year, the 30-year average (current climate data is based on 1981-2010), and what percentile we were (a 16th percentile means that 16% of years were below us, and 84% were above us).
| Measure | 2019 | Average | Percentile |
| Maximum Temperature (the highest we got all summer) |
103° | 104.7° | 20% |
| Days with highs above 99° | 6 | 8 | 34% |
| Days with highs above 89° | 49 | 41 | 86% |
| Mean High (the average of all the high temperatures this summer) |
89.7° | 87.8° | 84% |
| Maximum Low (the warmest low temperature this summer) |
70° | 70.9° | 41% |
| Mean Low (the average of all the low temperatures this summer) |
57.3° | 56.8° | 59% |
| Days with lows below 60° | 58 | 64 | 41% |
| Days with lows below 50° | 10 | 14 | 52% |
| Minimum Temperature (the lowest we got all summer) |
41° | 43.9° | 14% |
Some things, such as this year’s maximum temperature (103°), don’t seem too far from average (104.7°) but that’s why I included percentiles here. Many of these statistics have very narrow ranges, and maximum temperature is a good example of this. While this year’s maximum was only 1.7° below the average maximum, about 80% of the values for the current climate period were above it. I wouldn’t call this value “statistically significant” because it is certainly within the realm of possibilities, but it is pretty well removed from the average.
How I would interpret this data is to say that we were above average as a whole, while at the same time being less extreme. Our low temperatures were quite a bit closer to climatological norms, though we did have one morning that reached a chilly 41°. Only 14% of summers from 1981 to 2010 had a colder temperature.
As far as temperatures overall go (our mean temperature), if we go back all the way to 1894 (when records started in the Tri-Cities), say number 1 is the coldest and number 122 is the warmest, this summer comes in at 92. The reason why 125 isn’t warmest is because there are a few years with missing records.
Switching gears to rainfall now, here are the numbers for that:
| Measure | 2019 | Average | Percentile |
| Total Precip. | 0.37″ | 0.93″ | 9% |
| Precip. Days | 9 | 9 | 62%* |
*Note: The reason why the percentile for precipitation days isn’t 50% is because there have been more years below nine days than above. Years that had an unually high number of rainfall days pull the average a bit higher. Because of this, median is probably a better measure for this value. The median is eight.
What I find interesting here is that while we were at the average for precipitation days, we were well below average for total precipitation. Despite what seemed like multiple days of summer thunderstorms in the mountains, Meacham (up in the Blue Mountains between Pendleton and La Grande) was also well below average for total rainfall.
At the end of May, the Climate Prediction Center placed us as having a decent chance of an above-average summer, and it looks like this verified. Kudos to them. It’s always exciting to see long-range forecasts succeed.
Finally, you may recall an article I wrote last Spring (Does a snowy winter lead to an unusually hot summer?) after I had been asked if our crazy February/March snowfall could indicate a really extreme summer. Going through the data, I came to the conclusion that “there’s no way to make any sort of reliable prediction based on winter snowfall alone.” It seems that this year was a good example of that.
For the first half of the summer, we actually spent a bit of time under the same weather pattern that brought us a lot of snow in February. This was a high-pressure system that brought unseasonably warm temperatures to Alaska. During this period, Anchorage actually broke their all-time record high temperature. What this did for us is direct the jet stream around the high, pushing it toward the Arctic before dropping south through British Columbia and into the Pacific Northwest. In a sense, we can at least partially thank Alaska for our seemingly pleasant summer.
*Note: The reason why the percentile for precipitation days isn’t 50% is because there have been more years below nine days than above. Years that had an unually high number of rainfall days pull the average a bit higher. Because of this, median is probably a better measure for this value. The median is eight.
