by nathan oster
The first few days in August finally brought some relief from an unrelenting stretch of hot and dry conditions across south Big Horn County.
While it may fall short of setting a record, the summer of 2012 has been one of the warmest on record — not only in Greybull but also in Basin, where historical data is more readily accessible.
According to Chris Jones, a meteorologist with the National Weather Service in Riverton, last month was the fifth warmest on record in Basin, where records date back to 1899.
In fact, July’s average daily temp in Basin — which, it should be noted, is simply an average between the measured high and low for each day — was 77.8 degrees, which is 4 degrees above normal.
The warmest July in Basin’s history occurred in 2007 — when the average temp came in at 79.2 degrees. That year, there was no cooperative observer measuring temperatures in Greybull, so Jones was unable to compare “apples to apples.”
But it was clearly a hot month in Greybull as well, he said. Using figures from the airport (which often provides higher readings during the summer months), he put the July 2007 average for Greybull at 80.2 degrees.
While Greybull’s date is sketchier, Jones was able to draw some conclusions about the summer of 2012. Greybull has had a weather station in town since 1951, it was a “rain only” station until the mid to late 1980s.
So to get a sense of where Greybull’s summer ranks all time, Jones cautions that no information is available from prior to the mid 1980s.
That said, he drew comparisons to the summers of 2002 and 2003.
Summer of 2012
Prior to the rainfall and a 24-48 hour break in the heat on Friday and Saturday, Greybull had been on quite a streak of hot weather.
Reading taken by Doug Scott, the NWS’s cooperative observer, show that there was just one day between June 23 and July 31 in which the mercury did not top 90 degrees. That came on July 6, when there was an 82-degree reading. Ten times this summer, the high topped 100 degrees, maxing out with 105-degree readings on June 25 and July 4.
For July, the average high in Greybull was 95.5 degrees.
As for the “dry” part of the equation, Jones said Greybull went from June 10 through July 3 without any measurable precipitation. Since May 27, just .36 of precip have fallen in Greybull.
How does that compare to other hot summers?
Jones said the average temp in July of 2012, 76.9 degrees, is a tick below the average temps in July of 2002 (77.0 degrees) and July of 2003 (77.3 degrees).”
“Those were the only two years in that period (since the mid 1980s) that were warmer,” he said, adding that the average July temperature during that span has been 73.7 degrees.
“The interesting thing is, in 2002, we had a warmer start to the summer and by August, temperatures were below normal,” Jones said. “In 2003, we had a cooler start, but then we just blazed through July and August.”
So far in August, the average temp in Greybull has been 71.3 degrees. In June, the average temp was 68.5 degrees, which was the third warmest June since the mid 1980s and 3 degrees above the average for the 30-year period.
“That’s pretty much what we’re seeing everywhere around the state,” said Jones. “We had a very warm start to the summer. June was one of the warmer starts we’ve seen — certainly in the top 10 or very close to that. And July was very warm, with not much relief coming in terms of precipitation.”