Mother Nature is playing by the book this month, bringing some of the hottest temperatures of the season right on schedule.
The last week of July and first week of August are climatologically the hottest times of the year. Though average highs (a 30-year average) for the Spokane/Coeur d’Alene area are in the upper 80s, the threat for triple-digit temperatures is usually looming toward the end of the month.
A high temperature of 100 often gets a lot of press, not because it’s inherently more dangerous than highs in the upper 90s, but mainly because breaking into triple digits is pretty rare in this area. In Spokane, only eight of the past 19 summers saw temperatures reach or exceed 100 degrees. Fortunately, even during significant heat waves, the lack of humidity makes these conditions a bit more tolerable than what is experienced east of the Rockies.
In areas where the air is much more moist this time of year, such as in the South, air temperatures of 100 degrees or higher are not particularly common either. Once humidity is factored in, however, heat indexes exceeding 100 degrees can lead to dangerous conditions for those who cannot find a place to cool off. The high humidity also keeps nighttime temperatures stiflingly hot (in the 70s and 80s), which leads to further discomfort.
The hottest daytime temperatures are in dry, lower elevation areas – think deserts or Death Valley. The record high temperature for the country, 134 degrees, was set in Death Valley in July 1913. Don’t think elevation makes a huge difference? On July 15, 1972, in Death Valley, the official temperature recorded in an instrument shelter five feet off the ground was 128 degrees. The temperature recorded on the ground was 201!
Closer to home, places like Lewiston or Moses Lake often see multiple 100-plus degree days each year. Again, the atmosphere that allows the temperatures to make such a quick climb during the heat of the day also allows for significant cooling during nighttime.
The all-time record-high temperature for Spokane is 108 degrees, set in August 1961 and July 1928. Coeur d’Alene went one higher with 109 degrees in August 1961. Since record-keeping began, June has been pretty safe from 100-degree temps, reaching them for only three days. The most consecutive days at or above 100 degrees was six days, July 23 through 28, 1928.
For now, it looks like the long-range computer models, crunching numbers into next week, show little movement in our hot summer ridge pattern. Don’t expect a cool reprieve anytime soon.