AgWeatherNet July 2015 Weather Review for Washington

Abnormal Heat Continued in July

Nic Loyd, Meteorologist, 509-786-9357
Gerrit Hoogenboom, Director, 509-786-9371

Overview
July was another scorching and dry month in Washington, as Mt. Vernon experienced their warmest month on record (mean and high temperature). While areas east of the Cascades were rather hot, at least last month was generally not record-breaking. The bulk of the oppressive heat occurred during the first third of the month and again at the end, with somewhat more seasonally hot temperatures for the mid to late July period.

Conditions were sunny, sizzling, and dry for the first ten days of the month. On July 3rd, the high was 109 degrees at Orondo, while the low temperature was 83 degrees at Wahluke Slope. Later, on July 9th, Whitcomb Island concluded a streak of 14 consecutive days above 100 degrees. The pattern shifted slightly toward less hot conditions for mid month. Interestingly, 0.83 inches of rain fell at Anatone on the 11th.

The end of July was noteworthy for its highly changeable character. Highs on the 19th spiked as high as 105 degrees at Peshastin, before cooling slightly. The weather became quite cool on the 26th, as a storm system passed through Washington. There were clouds, breezes, and even some showers. The high at Pullman was only 66 degrees on the 27th, which was their coolest high since June 3rd, while the low was 39 degrees at Ritzville, which was their coolest since June 13th.

The period from July 25th to 27th was particularly surprising given that it was Washington's first stretch, albeit brief, of below normal temperatures in a long while. In fact, January 2nd was the last time that Prosser recorded a day that was as far below normal as was July 26th. Of course, that is more indicative of the warmth of 2015 than of the relative chill of July 26th. Alas, heat returned at month's end, as Benton City climbed to 108 degrees on the 31st.

The last rainfall at Prosser was May 26th, which means that the duration of our present dry spell is ten weeks and counting. In fact, conditions were very desert-like at the end of July. Pullman experienced an unusually large diurnal swing (high minus low temperature) of more than 50 degrees on July 30th. Following a high of just 66 degrees on the 27th, Pullman reached 95 degrees on the 30th, as day-time temperatures warmed nearly 30 degrees in only 3 days. Overall, despite the late month cool spell, July temperatures were well above normal once again.

July 2015 Average Temperatures (°F)
Location (Period of Record) Maximum Anomaly Minimum Anomaly Mean Anomaly Soil Temperature
8 inches
Prosser (WSU IAREC; 1989-2015)
90.6
2.2
58.2
2.8
75.2
2.5
75.6
Moxee (1989-2015)
NA
NA
NA
NA
NA
NA
66.3
Mt Vernon (WSU NWREC; 1994-2015)
77.7
4.8
55.2
2.7
65.9
3.7
66.3
Wenatchee (WSU TFREC; 1994-2015)
92.3
3.2
65.0
4.5
79.2
3.6
83.4
Tri-Cities (1995-2015)
95.6
3.5
64.3
3.8
80.8
3.6
89.9
Walla Walla (1993-2015)
91.6
3.4
63.6
3.9
77.7
3.4
84.2
Moses Lake (1989-2015)
91.7
3.9
60.1
3.8
76.5
3.7
85.0
Omak (Pogue Flat; 2005-2015)
91.0
NA
61.1
NA
76.8
NA
81.5
Royal City East (2008-2015)
89.0
NA
61.0
NA
75.0
NA
83.5
Pullman (2008-2015)
85.1
NA
52.1
NA
69.9
NA
75.9
Long Beach (WSU Long Beach; 2005-2015)
70.4
NA
52.6
NA
61.7
NA
67.6
Sequim (2008-2015)
76.2
NA
52.9
NA
64.7
NA
64.8
Seattle (2011-2015)
82.5
NA
59.0
NA
70.1
NA
77.2
Vancouver (WSU RE; 2008-2015)
84.9
NA
56.7
NA
71.2
NA
70.3
2015 Rainfall and Evapotranspiration (ET) (inches)
Location (Period of Record) Rainfall ET Net
July 2015 July (Rain - ET)
Prosser (WSU IAREC; 1989-2015)
0.00
3.61
9.93
-9.93
Moxee (1989-2015)
0.00
2.62
8.61
-8.61
Mt. Vernon (WSU NWREC; 1994-2015)
0.11
12.97
6.34
-6.23
Wenatchee (WSU TFREC; 1994-2015)
0.00
4.37
10.88
-10.88
Tri-Cities (1995-2015)
0.00
3.72
12.17
-12.17
Walla Walla (1993-2015)
0.05
7.61
9.27
-9.22
Moses Lake (1989-2015)
0.01
2.90
10.93
-10.92
Omak (Pogue Flat; 2005-2015)
0.10
3.33
8.88
-8.78
Royal City East (2008-2015)
0.00
2.30
9.78
-9.78
Pullman (2008-2015)
0.19
8.48
10.45
-10.26
Long Beach (WSU Long Beach; 2005-2015)
0.16
23.36
4.60
-4.44
Sequim (2008-2015)
0.17
7.78
6.09
-5.92
Seattle (2011-2015)
0.30
13.99
6.72
-6.42
Vancouver (WSU RE; 2008-2015)
0.62
15.15
8.14
-7.52
July 2015 Daily Rainfall Time Series Graph for Long Beach

July Weather
Early July-Scorching and Dry
July began with very hot and dry conditions statewide. Many central areas were consistently above 100 degrees during the day, and only in the 70s and 60s at night. On the 9th, Whitcomb Island completed a stretch of 14 consecutive days (dating back to June 26th) of highs above 100 degrees.

Mid July-Slight Relief Arrives
Mercifully, the incredibly persistent heat of early July subsided briefly around mid month, as highs fell into the 80s and 90s (70s) in the east (west). There were breezy periods, and even isolated rainfall in parts of eastern Washington, including 0.83 inches at Anatone on the 11th. Heat returned late in the period, as Peshastin reached 105 degrees on the 19th.

Late July-Variable Weather
Moderate conditions became quite cool and unsettled on the 25th. Pullman reached only 66 degrees on July 27th, which was their coolest high temperature since June 3rd, while Ritzville fell to 39 degrees, and the wind at Lind gusted to 34 mph. However, a strong warming and drying trend sent temperatures soaring to 101 degrees at Vancouver on July 30th.

July 2015 Daily Temperatures
2015 temperature Time Series Graph for Prosser 2015 temperature Time Series Graph for Moxee
2015 temperature Time Series Graph for Wenatchee 2015 temperature Time Series Graph for Tri-Cities
2015 temperature Time Series Graph for:Walla Walla July 2015 Temperature Time Series Graph for WSU
July 2015 Temperature Time Series Graph for WSUMoses Lake July 2015 Temperature Time Series Graph for WSU Omak
July 2015 Temperature Time Series Graph for WSU Long Beach July 2015 Temperature Time Series Graph for WSU Mt. Vernon

July-By The Numbers
The average July temperature at Prosser (WSU IAREC) was 75.2°F, which is 2.5 degrees above average. The average high temperature was 90.6°F, which is 2.2 degrees above average. The average low temperature was 58.2°F, which is 2.8 degrees (1.1 standard deviations) above average. The maximum temperature recorded last month was 104.3°F on July 31st, while the coolest daily high was 77.0°F on July 26th. Low temperatures ranged from 70.8°F on July 5th to 48.2°F on July 26th. Daily average temperatures ranged from 83.7°F on the 2nd to 64.2°F on the 26th. The monthly precipitation total was 0.00 inches. The average wind speed was 4.1 mph, and the average 8 inch soil temperature was 75.6°F. Wenatchee (WSU TFREC) recorded an average temperature of 79.2°F, which is 3.6 degrees above average, while Walla Walla's average monthly temperature of 77.7°F was 3.4 degrees above average. Pullman was one of the cooler spots in eastern Washington, with an average July temperature of 69.9°F. In western Washington, Mt. Vernon's average temperature was 65.9°F, which is 3.7 degrees above average.


Notable July Events
  • July 3rd: The low temperature at Wahluke Slope was a sultry 83 degrees.
  • July 3rd: The high temperature at Orondo was a scorching 109 degrees.
  • July 11th: 0.83 inches of rain fell at Anatone.
  • July 24th: 0.6 inches of rain fell at Nooksack.
  • July 26th: 0.43 inches of rain fell at Woodinville.
  • July 27th: The high temperature at Pullman was only 66 degrees.
  • July 27th: The low temperature at Ritzville was just 39 degrees.
  • July 31st: The high temperature at Benton City was 108 degrees.

July Temperature Extremes (°F)
  Observed in 2015 Record Monthly Extremes
Site (Period of Record) Warmest Date Coldest Date Warmest Date Coldest Date
Prosser (WSU IAREC; 1989-2015)
104.3
7/31/2015
48.2
7/26/2015
109.9
7/12/2002
38.7
7/3/1999
Moxee (1989-2015)
106.2
7/31/2015
39.8
7/27/2015
107.5
7/12/2002
NA
NA
Mt. Vernon (WSU NWREC; 1994-2015)
91.5
7/19/2015
48.9
7/17/2015
96.1
7/29/2009
43.2
7/3/2000
Wenatchee (WSU TFREC; 1994-2015)
103.9
7/31/2015
56.3
7/30/2015
106.6
7/23/2006
43.4
7/18/1996
Tri-Cities (1995-2015)
106.1
7/3/2015
54.1
7/28/2015
110.1
7/23/2006
46.0
7/3/1999
Walla Walla (1992-2015)
105.1
7/31/2015
53.3
7/28/2015
107.3
7/12/2002
42.6
7/11/2008
Moses Lake (1989-2015)
103.6
7/31/2015
49.8
7/29/2015
107.8
7/23/2006
42.4
7/2/1989
Omak (Pogue Flat; 2005-2015)
104.0
7/3/2015
49.1
7/28/2015
105.5
7/23/2006
42.8
7/11/2008
Royal City East (2008-2015)
102.0
7/3/2015
51.7
7/22/2015
102.0
7/3/2015
46.1
7/1/2011
Pullman (2008-2015)
98.1
7/31/2015
40.0
7/29/2015
98.1
7/31/2015
31.2
7/11/2008
Long Beach (WSU Long Beach; 2005-2015)
86.7
7/18/2015
46.1
7/8/2015
95.5
7/7/2010
38.5
7/2/2009
Sequim (2008-2015)
88.5
7/30/2015
45.0
7/29/2015
91.8
7/28/2009
34.6
7/1/2009
Seattle (2011-2015)
95.8
7/19/2015
55.1
7/28/2015
NA
NA
NA
NA
Vancouver (WSU RE; 2008-2015)
101.4
7/30/2015
49.7
7/27/2015
104.1
7/29/2009
40.3
7/31/2008

Agriculture Report
Heat and water stress continued to cause problems for Washington growers in July. As of July 12th, blueberry harvest was in full swing, and pumpkins were in full bloom. Peach harvest began while apricot harvest waned. Junior water rights producers in Yakima County reported crop loss. Winter wheat harvest was underway, and below normal yields were expected. As of July 26th, grass seed harvest was complete, and spinach harvest was expected to begin shortly. Plums and peaches became ripe in late July, and apples were sizing well. Recent heat caused sunburn damage on some grapes, and peaches were sprayed for powdery mildew prevention. Hops were in bloom, as Bartlett pear harvest neared. Some junior water rights holders had their water closed down (National Agricultural Statistics Service).

April 1 to July 31 Accumulated Growing Degree Days
  Base Temperature (°F)
32 43 50
Location 2015 5 Year Avg Difference 2015 5 Year Avg Difference 2015 5 Year Avg Difference
Prosser (WSU IAREC)
4084
3623
461
2743
2289
454
1925
1504
421
Tri-Cities
4537
3987
550
3198
2647
551
2360
1832
528
Walla Walla
4210
3704
506
2872
2367
505
2047
1573
474
Wenatchee (WSU TFREC)
4537
3837
700
3016
2502
514
2204
1710
494
Moxee
3781
3307
474
2448
1988
460
1690
1256
434
Omak (Pogue Flat)
4093
3576
517
2751
2248
503
1966
1493
473
Moses Lake
4139
3663
476
2797
2328
469
1981
1539
442
Pullman
3242
2791
451
1929
1510
419
1218
855
363
Royal City East
4145
3633
512
2804
2297
507
1988
1516
472
Mt. Vernon (WSU NWREC)
3295
2946
349
1953
1609
344
1143
834
309
Long Beach (WSU Long Beach)
2772
2563
209
1431
1230
201
671
504
167
Sequim
3079
2681
398
1737
1354
383
983
643
340

GDD are calculated by subtracting a base temperature from the average daily temperature (°F). If the resulting value is less than 0, then it is set to 0. Thus GDD are always 0 or greater.

GDD = (Tmax+Tmin)/2 - Tbase


This Month in History
On July 23, 2006, the temperature at WSU Tri-Cities soared to 110 degrees.

Climate Outlook
According to the Climate Prediction Center, above normal temperatures and below normal precipitation are very likely for the remainder of 2015 and well into 2016. Moderate to strong El Niño conditions continue, and a strong event is expected to peak during the late autumn or early winter.

Washington State University