August 2018 Temperature and Precipitation Summary Arizona Climate Summary September 2018 Summary of conditions for August 2018 August 1 st 15 th : August began with high pressure centered over the state and scattered rain showers.. Rain fell every day somewhere in the state through the 27 th of the month. During the first 5 days, the rainfall totals included 0.31 at Bisbee-Douglas, 1.11 at Flagstaff, 0.24 at the Grand Canyon, 0.49 at Kingman, 0.11 at Page, 0.05 at Phoenix Airport, 1.05 at Prescott, 0.92 at Sonora Desert Museum, 0.26 at Tucson Airport, 0.34 at Window Rock, 0.23 at Winslow, 0.20 at Cottonwood, 0.55 at Douglas, 0.13 at Eloy, 0.02 at Payson, 0.28 at Seligman and 0.19 at Show Low. Daily rainfall amounts picked up significantly through the 15 th with 0.50 at Bisbee-Douglas on the 6 th -7 th, 1.10 at Coronado on the 8 th, 1.06 at Pinnacle Peak on the 9 th, 2.01 at East Mesa on the 10 th, 2.80 at Carefree on the 11 th, 0.29 at Coronado NM and Phantom Ranch on the 12 th, 0.54 at Flagstaff on the 13 th, 1.31 at Flagstaff on the 14 th, and 1.07 at Safford on the 15 th. Daytime temperatures during the first week of August ranged from 111 to 114 o F in the southwest deserts and 79 to 88 o F at the higher elevations. Nighttime temperatures ranged from mid 70s to 91 o F in the southwest deserts 55 to 66 o F at the higher elevations. Both daytime and nighttime temperatures cooled off 5 to 10 degrees during the 2 nd week of August as storms became more widespread. August 16 th 31 st : Monsoon activity continued through the 27 th. From the 16 th through the 20 th, daily totals were less than 0.75 and daytime temperatures ranged from 102 to 110 o F in the southwest deserts and low to mid 50s in the higher elevations. Daily rainfall totals increased on the 21 st through the 25 th, with 0.85 at Grand Canyon Airport on the 21 st, 0.97 at the Grand Canyon North Rim on the 22 nd, 1.58 at Seligman on the 23 rd, 1.31 at Carefree on the 24 th, and 0.98 at Tucson on the 25 th. By the 28 th, the high pressure had moved to the east over Texas and dry air moved into the state. Rainfall the rest of the month was very light and spotty. No rainfall was reported on the 28 th or 29 th, and the heaviest rainfall was reported at Coronado National Monument, 0.05 on the 30 th and 0.02 on the 31 st. High temperatures ranged from 106 to 108 o Fin the deserts and 66 to 77 o F at the higher elevations. In This Issue: Overview of August, graphs of the August daily maximum and minimum temperatures, precipitation, mean daily dew points for Flagstaff, Phoenix, and Tucson; August climate statistics, maps of mean monthly maximum and minimum temperatures, precipitation, dew points, wind speeds for August; short-term drought maps for the beginning and end of August 2018; Long-term Drought Map through August and graphs of the mean August temperature and precipitation for the period of record for Tucson, Phoenix, and Flagstaff, graphs of the cumulative precipitation for the calendar year for Flagstaff, Phoenix, and Tucson. Climate calendars for Flagstaff, Phoenix, Tucson, Prescott, Winslow and Yuma, including daily and monthly normals and extremes, for each month of the year, are not yet updated through 2017. See p.21 of this report for calendar abbreviations. Data are preliminary and are from the National Weather Service Forecast Offices in Flagstaff, Phoenix and Tucson. **Note: The discrepancy between the Statewide Temperature and Precipitation values for Phoenix, Flagstaff and Tucson and the daily values in their graphs are due to the reporting times. Statewide Temperature and Precipitation values are taken at 5pm, while official daily records at the airports are taken from Midnight to Midnight. Dr. Nancy J. Selover, State Climatologist http://azclimate.asu.edu 480-965-0580 Edited by Nancy J. Selover 2018 Arizona State Climate Office 1
August 2018 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2
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FLAGSTAFF CLIMATE STATISTICS August 2018 This August was tied for 26 th warmest with 3 other years (1934, 1946, 1981) and was the 10 th wettest on record. Avg Max Temp(F) 79.4 Normal 78.4 Avg Min Temp(F) 51.5 Normal 50.1 Avg Mean Temp(F) 65.4 Normal 64.2 Departure from Normal (F) +1.2 Highest Monthly Avg Temp (F) 67.5 in 1944 Lowest Monthly Avg Temp (F) 59.5 in 1968 Highest Temp this month (F): 88 on 6 th & 7 th Lowest Temp this month (F): 44 on 28 th Record High (F): 93 on 8/02/1902 Record Low (F): 32 on 8/23/1968 Temperature or precipitation records this month: 14 th Precip 1.31 set, previous record 1.10 in 1909 Flagstaff Number of Days of: Minimum Temp 55 o F or higher 6 Minimum Temp 50 o F or lower 9 Maximum Temp 85 o F or higher 4 Maximum Temp 75 o F or lower 8 Heating Degree Days 35 Normal 56 Cooling Degree Days 57 Normal 33 Degree base 65 o F Total August Precipitation 5.15 Normal August Precipitation 3.11 Departure from normal +2.04 Greatest 24-Hr Precipitation 1.31 on 14 th Total Precipitation Year-to-Date 14.36 Departure from Normal +0.17 Total August Snowfall 0.0 Normal 0.0 Record August Snowfall 0.0 Number of Days: Clear 26 Partly Cloudy 5 Cloudy 0 Greatest August Precipitation 8.77 in 1904 Least August Precipitation: 0.26 in 1962. Average Wind Speed Highest Peak Gust 5.2 mph 37 mph from 200 o on 21 st PHOENIX CLIMATE STATISTICS August 2018 This August was tied for 21 st warmest on record with 2 other years (2010, 2017) and the 26 th wettest on record. Avg Max Temp(F) 105.0 Normal 104.4 Avg Min Temp(F) 83.1 Normal 82.7 Avg Mean Temp (F) 94.0 Normal 93.6 Departure from Normal (F) +0.4 Highest Monthly Avg Temp (F) 98.3 in 2011 Lowest Monthly Avg Temp (F) 84.6 in 1918 Highest Temp this month (F) 114 on 6 th Lowest Temp this month (F): 72 on 10 th Record High (F): 117 on 8/14/2015, 8/26/2011 Record Low (F): 58 on 8/20/1917 4 Temperature or precipitation records this month: 4 th HiMin 91 set, previous record 90 in 2009 6 th HiMax 114 tied, first set in 1995 10 th Precip 0.56 set, previous record 0.32 in 1958 20 th HiMin 90 set, previous record 88 in 2007 Phoenix Number of Days of: Minimum Temp 80 o F or lower 11 Minimum Temp 90 o F or higher 4 Maximum Temp 100 o F or lower 4 Maximum Temp 110 o F or higher 7 Heating Degree Days 0 Normal 0 Cooling Degree Days 907 Normal 885 Degree base 65 o F Total August Precipitation 1.50 Normal August Precipitation 1.00
Departure from normal +0.50 Greatest 24-Hr Precipitation 0.56 on 10th Total Precipitation Year-to-Date 2.97 Departure from Normal -2.31 Greatest August Precipitation 5.33 in 1951 Least August Precipitation 0.00 in 1973, 1975, 2002 Number of Days: Clear 12 Partly Cloudy 19 Cloudy 0 Average Wind Speed 7.4 mph Highest Peak Gust 64 mph from 50 o on 8 th TUCSON CLIMATE STATISTICS August 2018 This August was tied for 15 th warmest on record with 1998 and had no significant ranking for precipitation. Avg Max Temp(F) 98.0 Normal 97.4 Avg Min Temp(F) 75.0 Normal 73.3 Avg Mean Temp(F) 86.5 Normal 85.3 Departure from Normal (F) +1.2 Highest Monthly Avg Temp (F) 90.2 in 1994 Lowest Monthly Avg Temp (F) 80.8 in 1923 Highest Temp this month (F): Lowest Temp this month (F): Record High (F): 112 on 8/01/1993 Record Low (F): 55 on 8/20/1917 109 on 6 th 68 on 24 th Temperature or precipitation records this month: 5 th HiMin 84 tied, first set in 1944 6 th HiMax 109 tied, first set in 1995 Tucson Number of Days of: Minimum Temp 70 o F or lower 3 Minimum Temp 80 o F or higher 5 Maximum Temp 95 o F or lower 11 Maximum Temp 105 o F or higher 6 Heating Degree Days 0 Normal 0 Cooling Degree Days 671 Normal 631 Degree base 65 o F Total August Precipitation 2.71 Normal August Precipitation 2.39 Departure from normal +0.32 Greatest 24-Hr Precipitation 0.98 on 24 th Total Precipitation Year-to-Date 7.86 Departure from Normal -0.05 Greatest August Precipitation 7.93 in 1955 Least August Precipitation 0.08 in 1924 Number of Days: Clear Partly Cloudy Cloudy Average Wind Speed Highest Peak Gust M M M 6.7 mph 60 mph from 230 o on 1 st Data are from the National Weather Service and the National Climatic Data Center and are preliminary. 5
Wind Speeds for August: Day Phoenix Flagstaff Tucson (mph) Avg Max Avg Max Avg Max 1 6.2 29 6.3 24 4.7 60 2 9.1 54 3.7 25 6.2 30 3 4.9 22 4.6 24 5.9 27 4 5.8 21 5.4 26 7.2 22 5 7.2 24 6 33 6.5 22 6 7.2 25 3.9 22 8.9 31 7 11.5 39 4.7 25 8.8 49 8 9.4 64 8.1 25 7.9 36 9 8 51 5.8 26 5.9 24 10 9 45 3.1 22 6.8 33 11 7.9 38 4.9 36 6.8 34 12 7.6 58 6.2 23 7.9 39 13 7.1 33 7.1 26 6.5 27 14 9.4 39 5.5 27 7.3 36 15 6.4 25 3.1 17 4.9 18 16 8.9 29 4.4 22 7 21 17 6.5 26 2.7 13 6.2 19 18 6.7 23 5 23 6.1 26 19 7.8 19 3 16 6.4 24 20 6.7 21 5.1 28 8.4 56 21 8.9 24 7.8 37 5.8 20 22 11.4 25 6.3 24 6.5 39 23 7.5 42 3.1 21 8 30 24 6.9 56 3.5 17 8.4 46 25 5.8 19 2.5 26 6.3 26 26 6.3 21 6.6 26 6.4 20 27 8.3 20 11.1 33 6.5 25 28 4.7 26 6.8 30 6.5 18 29 4.8 16 4.3 23 7.1 38 30 5.9 19 5.5 23 6.2 23 31 5.5 20 6.1 29 5.6 20 Dew Points for August: Daily Average Dew Point ( o F): Day Flg Phx Tuc 1 59 63 54 2 61 61 54 3 60 59 52 4 57 55 50 5 51 54 43 6 57 56 38 7 60 60 47 8 64 63 47 9 65 64 50 10 64 62 52 11 64 62 52 12 62 61 50 13 65 62 51 14 64 63 51 15 67 65 52 16 66 65 55 17 66 65 55 18 64 64 50 19 62 63 52 20 60 61 52 21 64 63 53 22 64 65 53 23 67 63 53 24 66 64 54 25 64 65 52 26 54 62 49 27 48 59 42 28 46 53 37 29 52 55 40 30 57 56 44 31 57 54 44 6
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August 2018 The minimum temperatures ranged from 30 o F at Meteor Crater and Hannagan Meadow to 79 o F at Goodyear Airport. The lowest maximum temperature of 74 o F was recorded at Snowslide Canyon and the highest was 120 o F at Havasu. The highest rainfall totals were 7.40 at Kitt Peak and 7.08 at Prescott. The lowest average dew point was 40 o F at Flagstaff and the highest was 66 o F at Coolidge and Sahuarito. The highest peak wind gust was 53 mph at Mesa and 51 at Maricopa. Average wind speeds ranged from 3 mph in many locations to 13 mph at Kingman. 8
T August 2018 The highest average minimum temperature was 87 o F at Laughlin-Bullhead City, and the lowest average minimum temperature was 40 o F at the east entrance to the Grand Canyon. The highest average maximum temperature was 112 o F at Bullhead City and Havasu and the lowest average maximum temperature was 67 o F at Snowslide Canyon. 9
Short term drought maps for July 31 st on left and August 28 th on right. The monsoon activity in central and southern Arizona has led to removal of Exceptional Drought (D4) along the Maricopa/Gila County border and reduction of Extreme Drought (D3) in central Maricopa and western Pinal and Pima counties. Exceptional Drought (D4) dropped from 10.55% of the state to 8.62%. Extreme Drought has been reduced from 47% to 40%. While monsoon precipitation has benefitted northern and eastern Arizona, the greatest improvement has been in southeastern Arizona which was the big loser during the winter wet season. 10
The long-term drought map for August shows hydrologic drought, and this month it is based on precipitation and evaporation using the Standardized Precipitation Evaporative Index (SPEI) over the past 24-, 36-, and 48- months. This depiction is for water resources, not short-term drought (rangeland conditions). Though much of Coconino and northern Mohave County show up as abnormally dry or moderate drought, there are significant water resource issues, such as wells going dry and water hauling. A few small areas in Mohave and southwestern La Paz County show No Drought (white), but this is due to a lack of data around those locations. 11
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August August minimum temperatures were 0-2 o F warmer than average across most of the state with a couple of cooler than normal spots in southern Navajo and Apache counties, eastern Gila County, and the Yavapai/Coconino/Gila County borders. Northern Coconino and southern Mohave counties were 2-6 degrees warmer than normal. Daytime temperatures have been 1-4 o F warmer than average across northern and southeastern Arizona. South Central Arizona has been 0-3 o F cooler than average, largely due to storm events. Rainfall has been much greater than average across central Arizona, but less than average in eastern and western Arizona. 13
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Calendar Year 2018 Calendar year minimum temperatures across Arizona have been 1 to 3 o F warmer than average, though a few spots have been slightly cooler than average. Daytime temperatures have been 1 to 3 o F warmer than average in southern Arizona and 2-5 o F warmer than average in the northern half of the state. In spite of the wet August in central Arizona, this area, along with northeastern and southwestern Arizona, has received less than 70% of average precipitation. A few spots have received near average or above average precipitation this calendar year. 15
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s aham, Cochise, La Paz, OPima and 2018 Water Year Water Year 2018 minimum temperatures have ranged from 1-3 o F warmer than average in central and southern Arizona and Coconino County, while Apache, Navajo, and La Paz counties have had some cooler than average temperatures. Daytime temperatures in the state have been 2 to 6 o F warmer than average mostly due to the lack of cold winter storms. The monsoon rainfall has not yet been enough to make up for the significant deficits left by the dry fall, winter and spring.. Most of the state has still received less than 70% of normal precipitation and many areas have received less than 50%. Only September remains to make up this deficit. 17
August Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2018: 18
August Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2018 19
2018 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff is 0.17 above normal, Phoenix is 2.31 below normal, and Tucson is 0.05 below normal. 20
The downloadable normals and extremes calendars use the following abbreviations: NORM = 30 year (1971-2000) average value (degrees Fahrenheit (F)) OBS = The temperature observation for that day this year AVG = Average daily temperature HI MAX = Highest maximum temperature for that day (F) LO MAX = Lowest maximum temperature for that day (F) LO MIN = Lowest minimum temperature for that day (F) HI MIN = Highest minimum temperature for that day (F) Mx PCP = Maximum precipitation for that day (inches) Mx SNO = Maximum snowfall for that day (inches) 21