Summer 2022 Season in Review

Temperatures were above or much above normal across most of the region. Precipitation was below or much below normal across Baker County Oregon and most of southwest Idaho. Only Harney and Malheur Counties, the lower Treasure Valley, and the southwest corner of Owyhee County were wetter than normal due to Pacific storms during the first half of June and monsoon thunderstorms in Harney, Baker, and southwest Owyhee Counties in August. 


June 2022 precipitationJune 2022 temperature

The first half of the month was dominated by westerly winds across the North Pacific which brought changeable weather to the northwestern U.S. Weather systems carried inland nearly daily showers from the 4th through the 8th.

On the 5th and 6th an upper level trough weakened as it moved inland, but it retained enough moisture and energy to generate strong thunderstorms across much of southwest Idaho. Hail up to 1.25 inches was reported at a number of locations.  Rainfalls  up to 1.25 inches were also measured. 

On the 10th warm air spreading north from the Great Basin raised temperatures above normal.

On the 12th a deep upper level trough, which had tapped abundant subtropical moisture, pushed inland. The cold front in advance of the trough was followed by a second front as the trough approached. The fronts triggered thunderstorms and heavy showers which dumped over an inch of rain at several locations. In Harney County north of Andrews a Mesonet station at Little McCoy Creek measured 2.23 inches. A Mesonet stations near Featherville in Elmore County measured nearly 3 inches. Local flooding was common around the region.  Wind gusts from 40 mph to around 50 mph were observed at several locations. 

The trough lingered through the 15th, keeping temperatures around 15 degrees below normal. Twin Falls recorded a record low of 37 on the 14th. On the 15th a record low of 26 was set at Burns.

Temperatures quickly rebounded on the 16th under southwest flow aloft ahead of the next trough. 

The cold front ahead of the trough moved into western Idaho late on the 16th. It stalled west of the Magic Valley, and Twin Falls recorded a record high of 94 on the 17th. Behind the front that same day highs were 10-15 degrees cooler.  The front finally exited east of our area late on the 17th, and the trough following the front kept temperatures 5-10 degrees below normal through the 20th.

By the 21st westerly flow aloft along the Canadian border had carried the trough east, allowing temperatures to recover to near normal.

On the 23rd a trough from the Gulf of Alaska had drifted south to southern B.C. and the Idaho panhandle. The cold front crossed the Boise area that afternoon, resulting in below-normal temperatures on the 24th and 25th. A record low of 41 was set at Twin Falls on the 25th.  

The trough rapidly exited eastward across southern Canada , allowing a very warm high amplitude ridge to build over the Intermountain Region, and the first really hot weather of the summer ensued. Highs from the mid 90s to a few degrees over 100 were common at lower elevations from the 26th through the 28th

A weak upper level trough moved over the area on the 29th, lowering  temperatures to near normal through the 30th.


July 2022 precipitation July 2022 temperature

On the 1st and 2nd a weak upper-level ridge and southwest flow aloft supported highs 5-10 degrees above normal.

On the 3rd an upper-level trough, which had been centered over Vancouver Island, began to edge inland. Cooler Pacific air associated with the trough lowered temperatures to near normal on the 3rd and below normal on the 4th.  Following the cold front on the 3rd, a wind gust of 67 mph at the Boise Airport knocked out power to the NIFC (National Interagency Fire Center).

Blocked by the ridge, the trough retreated back offshore on the 5th, allowing highs to rebound from the 5th through the 9th.

The trough moved back inland on the 9th, weakening as it encountered the strengthening ridge. The trough retained enough energy to spark thunderstorms. One storm produced three-quarter inch hail at Council. 

The ridge continued to strengthen and expand, and by the 12th it covered all of the western and south-central contiguous states.  Highs reached or exceeded 100 at lower elevations each day from the 12th through the 17th. 

A downburst from a thunderstorm at Burns on the 12th generated a wind gust of 67 mph. 

Meanwhile, another trough had migrated from the Aleutians across the Gulf of Alaska before crossing Washington and northern Idaho on the 18th. Cool air filtering south prevented temperatures from rising above 90 at most locations.

The trough continued on its eastward trek, allowing the ridge to expand northward again. Highs reached or surpassed 100 on the 20th in the lower valleys. 

Highs were around 5 degrees cooler from the 22nd through the 25th under the influence of a weak trough.

A new ridge developed off the coast and began to work its way inland on the 26th, resulting in another series of 100+ highs from the 26th through the 31st. 

Date       Location         Record high
7/17       Burns            100
           Twin Falls       100 tied record set in 2010
7/25       Burns             98 tied record set in 2021
7/26       Burns            102
7/27       Burns            101 tied record set in 1939
           Ontario          107 tied record set in 1964
7/28       Burns            103
           Ontario          109 
7/29       Boise            104 tied record set in 1934 
           Burns            103
           McCall            95 tied record set in 1994
           Ontario          111 national high!
7/30       Burns            103 tied record set in 2003
           McCall            96
           Baker            101 tied record set in 2003
7/31       Burns            104
           Ontario          102


On the 31st at Baker a thunderstorm downburst produced a gust of 62 mph. 


August 2022 precipitation August 2022 temperatures

A persistent upper level high pressure ridge was responsible for the record-setting heat.  On the 2nd as a Pacific cold front trailing south from Canada lowered highs by 10-15 degrees.  Temperatures rebounded on the 3rd and 4th ahead of the next Pacific cold front. That front passed on the 5th and lowered highs a few degrees on the 5th and 6th.

Warmer air returned on the 7th, and on the 8th highs exceeded 100 in the lower valleys.

On the 9th the ridge was centered over Wyoming and Colorado. Southerly flow between the ridge and an upper level low pressure center off the northern California coast began to pull monsoon moisture north over our area, resulting in scattered  thunderstorms from the 10th through the 12th

On the 10th there were reports of thunderstorm outflow gusts to around 60 mph in Malheur and Owyhee Counties. Heavy rain on the slopes of the Owyhee Mountains caused Rabbit Creek near Murphy to flood, with water over roads in places. A trained spotter at Murphy measured .78 of an inch of rain in 40 minutes. A spotter four miles southwest of Murphy measured 1.2 inches. 

On the 11th hail .5 to 1.5 inches in diameter fell at several locations in Canyon, Payette, and Owyhee Counties. On the 12th a trained spotter reported 1.5 inch hail at Oxbow Dam in Baker County, and a spotter at Yellow Pine reported 1.75 inch hail. 

On the 13th the low pressure center finally moved inland over southwest Canada. This allowed the upper level flow to shift into the southwest, bringing much drier air. 

From the 14th through the 24th highs in the valleys ranged from mid 90s to just over 100.

Monsoon moisture returned late in the day on the 18th as a weak low pressure trough approached from northern California. No unusual rainfalls were reported from thunderstorms on the 19th, but reports on social media described trees and power lines knocked down two miles northwest of McCall. The strongest gust measured at McCall airport was 45 mph. 

The heat persisted through the 26th.

By the 27th the upper level ridge center had relocated westward between Alaska and Hawaii, so flow across the North Pacific was no longer blocked from entering the northwest U.S. On the 27th a dry cold front crossed our area, resulting in a very pleasant weekend with highs near normal on the 27th and 28th.

On the 29th the upper level ridge over the Intermountain Region was already rebuilding, and temperatures were on their way up again.   The 106 at Boise on the 31st was the warmest ever so late in the season. 


Date         Location                 Record high
8/1          Burns                    100 tied record set in 2015
             McCall                    94
             Ontario                  109
8/13         Twin Falls                96
8/17         Boise                    103
             Burns                    103
             McCall                    97
             Twin Falls                99
             Baker                     99 tied record set in 2020
8/29         Burns                     95 tied record set in 2017
8/31         Boise                    106
             Burns                    101
             McCall                    95
             Ontario                  102
             Mountain Home            104
             Jerome                    99 tied record set in 1916
             Twin Falls               101
             Baker                    102             

Season in Review – Summer 2021

Summer was, in a word, hot…the hottest on record at several locations. Many monthly and daily temperature records were broken or tied. It was also drier than normal overall, with the notable exception of the Treasure Valley.

June-August 2021 3-Month Averages vs  Previous Warmest              
               Summer 2021         Previous warmest
Boise              78.0                   76.6/2015
Baker City         67.2                   69.0/1961  
Burns              69.6                   69.2/1961
Jerome             74.2                   74.2/1961
McCall             65.6                   65.3/1961
Ontario            79.4                   78.5/1961
Rome               71.0                   72.4/2007
Twin Falls         73.9                   75.1/2013
June-August 2021 Monthly Averages vs Previous Warmest
             June               July               August
Boise        75.9  70.5/2007    83.8  83.1/2007    74.4  78.7/2001
Baker City   65.4  66.0/1961    71.3  72.3/1985    64.9  71.3/1961
Burns        66.9  66.9/2015    74.5  73.2/1960    67.3  72.3/1967
Jerome       73.5  71.8/1974    79.0  77.9/1985    70.1  77.3/1967
McCall       62.9  63.3/2015    71.1  68.7/2017    62.8  67.9/1961
Ontario      75.9  80.0/1971    85.1  82.3/2007    75.9  80.0/1971
Rome         68.9  72.4/2015    75.2  78.1/2007    68.8  74.2/1967
Twin Falls   72.2  73.5/2015    78.8  79.6/2007    70.6  77.1/2013
2021 Monthly Highs vs Previous Monthly Highs
             June               July              August
Boise        105  110/2015      107  111/1960     105  110/2018
Baker City   103  102/1961      101  105/2020      98  109/2018
Burns        103  102/2015      102  107/2002     101  103/2018
Jerome       100  110/1940      100  108/1973      99  107/1940
McCall        96   97/2015       95  102/1928      93  104/1928
Ontario      107  109/2015      107  113/1967     106  113/1961
Rome         101  107/2015      105  110/2002     103  107/2018
Twin Falls   100  103/2013      100  107/2003      96  102/2013


June temp anomalyJune precip anomaly

A persistent and very warm upper level high pressure ridge resulted in a number of record highs. It was the warmest June on record at Boise, Burns (tied), and Jerome.  The high of 103 at Boise on the 3rd was not only a new record for the date, it was also the highest for so early in the season.

A dry pacific cold front crossed the Boise area on the 4th, and temperatures were back to near normal from the 6th through the 9th.

A cold upper level low pressure trough from the Aleutians arrived at the northwest coast on the 7th. After deepening southward, it moved inland over the Pacific Northwest and northern California on the 9th and crossed the Intermountain Region on the 10th. The 0.71 inch of rain at Boise that day was only 0.04 inch short of Boise’s normal precipitation for the entire month of June.

Temperatures rose from the 11th through the 13th under southwest flow aloft ahead of an offshore trough.

As the trough moved inland on the 14th and 15th, the coolest air was diverted north of our area by an expanding upper level high pressure ridge over the four corners. So the trough brought only slight cooling, lowering temperatures to near normal on the 16th.

As the ridge amplified, temperatures rose again.

A low pressure trough formed off the California coast on the 20th. A disturbance generated by the trough lifted north, heading for southeast Oregon and southwest Idaho. It spawned strong, but mostly dry, thunderstorms in southeast Oregon on the 22nd. Cloud cover and cool air in the trough kept temperatures in the 60s and lower 70s in Harney County, while Boise`s high soared to 98 degrees. The increased pressure gradient caused by the temperature difference enhanced outflow from the storms as they drifted north, resulting in strong west winds in the Treasure Valley. A gust of 59 mph was measured at the Boise Airport, but there were reports of even stronger gusts elsewhere in the valley.

On the 23rd, an upper level ridge began to build off the coast. By the 26th it had moved inland over B.C. and the northwest U.S., unusually far north for such a strong and very warm ridge. Temperatures responded with a number of record highs from the 28th through the 30th.

During the hottest part of the day, humidities were low, falling into the teens and single digits.

Moisture circulating around the ridge resulted in numerous showers and thunderstorms around the region on the 30th, but many locations reported only sparse precipitation.



July temp anomalyJuly precip anomaly

July 2021 was the warmest on record at several locations, including Boise, Burns, Jerome, McCall, and Ontario.  It could have been even warmer. Persistent smoke from wildfires restricted sunlight from reaching the surface, so highs were slightly lower than they would have been under clear skies.

At Boise, several other temperature records were broken, tied, or approached.

Consecutive days
     highs >= 90...44(6/17 - 7/31) ranks 2nd (50 in 1875 ranks 1st)
           >= 100...9(6/28 - 7/6) ties 2015, 2006, and 2003 
     lows  >= 60...43(6/19 - 7/31) ranks 1st (37 in 2007 ranks 2nd)
           >= 70...11(6/27 - 7/7) ranks 1st (5 in 2015 ranks 2nd)
Number of days
     highs >= 90...31...ties July 2017 (30-year average is 22)
           >= 100...12...ranks 4th (15 in 2003 ranks 1st)
     lows  >= 60...31...ties July 2007 (30-year average is 20)
           >= 70...16...ranks 1st (9 in 2007 ranks 2nd)
                                 (30-year average is 3)

It was a dry month overall, but a storm on the 31st brought significant rain to many Idaho locations.

An upper level warm high pressure ridge was responsible for the heat. Weak cold fronts associated with Pacific weather systems crossing western Canada occasionally pushed far enough south to lower temperatures by a few degrees. But other than breezy northwest winds, they had little noticeable effect.

By the 20th the ridge had shifted east and was centered over Colorado. Southwest flow between the ridge and an upper level trough centered over the B.C. coast transported monsoon moisture north of the Nevada border. The resulting thunderstorms brought generally light precipitation, along with gusty winds.

On the morning of the 22nd, a cold front passed our area as the upper level flow began to shift into the west, carrying the monsoon moisture east. Cooler drier air following the front resulted in the below normal average daily temperatures from the 22nd through the 24th.

On the 28th a brief influx of monsoon moisture generated early morning showers and thunderstorms, but precipitation was sparse. Skies cleared, and it was another hot afternoon and evening. Drier southerly flow brought even higher temperatures on the 29th and 30th.

By the 26th the center of the upper level ridge had migrated to the central Great Plains. Easterly flow south of the ridge picked up very moist air from the Gulf of Mexico and carried it west to New Mexico and Arizona. Southerly flow on the west side of the ridge then transported it north to the northern Intermountain Region.

On the 31st a low pressure system formed over Nevada. As it moved north, it interacted with the Gulf moisture, setting off numerous showers and thunderstorms with locally heavy rain. The Boise and Ontario areas, the Magic Valley, southern Twin Falls County, and the central Idaho mountains got the brunt of the rain.




August temp anomalyAugust precip anomaly


In contrast to June and July, August was a relatively wet month with near normal temperatures, although it certainly had its share of record daily high temperatures. But smoky skies prevented highs from reaching their full potential. Temperatures were mostly above normal for the first half of the month and mostly below normal for the last half.

An upper level high pressure ridge kept temperatures hot from the 2nd through the 5th.

On the 6th a cold front and weak upper level trough crossed our area. Temperatures warmed briefly on the 7th ahead of a stronger trough from the Gulf of Alaska. That trough, and the northwest flow that followed, cleared the smoke and kept temperatures below normal through the 10th.

The heat returned on the 11th as an upper level ridge centered off the coast built inland. The heat persisted through the 16th. By the 14th the smoke had overspread our area again.

A major pattern change on the 17th ended the heat. An upper level trough deepened south from Canada over the Pacific Northwest and the Intermountain Region as an upper level ridge between Alaska and Hawaii strengthened and expanded north. The resulting northwest flow aloft put us in the path of more troughs coming out of Alaska. One of these systems brought light but measurable rain on the 20th and 21st, plus another brief respite from the smoke.