Arizona Climate Summary

August 2015 Temperature and Precipitation Summary Arizona Climate Summary September 2015 Summary of conditions for August 2015 August 1 st 16 th : August was a wet month across the state with only 3 days when no station reported rainfall, August 4, 18, and 19. The month began with high pressure over Texas and widespread rain across Arizona and New Mexico. The most intense rain on the 1 st was in the White Mountains with 1.20 at Springerville. The western third of the state was dry. Similar conditions continued through the 2 nd, with 1.04 at Navajo National Monument. On the 3 rd, the high pressure started to move westward, bringing drier air to most of the state. The eastern counties continued to have rain on the 3 rd with 1.10 at Canyon de Chelly. The high moved back toward New Mexico by the 6 th, and some light showers were reported across southern and eastern AZ on the 5 th and 6 th, 0.08 on the 5 th at Alpine, and 0.38 at Bouse on the 6 th. High temperatures the first week ranged from117 o F along the lower Colorado River to the upper 70s at Alpine and the mid-80s in Flagstaff. Significant rain returned on the 7 th with 1.52 at the Grand Canyon North Rim, and on the 8 th rain fell across most of the state with the highest value of 0.92 at Nogales. The high pressure remained over eastern Texas, leaving the western counties dry. Totals for the 9 th included 0.60 at Seligman and 0.55 at Bisbee. On the 10 th, Williams had 0.54 and Alpine had 0.64. The high pressure over Texas continued to push moisture into the state on the 11 th while a low pressure system developed off the California coast. On the 11 th, Grand Canyon North Rim reported 1.05 and on the 12 th, Show Low had 0.85. As the high moved into Utah, rainfall tapered off with amounts less than 0.30 from the 13 th through the 16 th. The low pressure system became cut-off and did not affect Arizona. Temperatures soared to 118 o F on the 15 th through the 17 th at Bullhead City, with 117 o F at Yuma on the 15 th, and at Phoenix Sky Harbor on the 14 th, setting a new record for that date. August 17 th 31 st : The high pressure moved directly over Arizona on the 17 th, and continued moving to the west, bringing in drier air, and restricting rainfall to the southeast corner of the state with 0.61 at Coronado National Monument. The 18 th and 19 th were dry and hot, but not record breaking. The high pressure remained over the northern Baja Peninsula through the 22 nd, keeping most of Arizona under a dry westerly flow of air. Rainfall was restricted to the southeast, with 0.31 at Elgin on the 20 th, 0.95 at Bisbee on the 21 st and by the 22 nd, the moisture had moved into northern Arizona and Bellemont had 0.44. Light showers did occur across central Arizona with Cottonwood reporting 0.10 on the 20 th, and Show Low reporting 0.05 on the 20 th. By the 23 rd the high pressure had moved back over the southwest and southerly flow brought more widespread moisture to the state which remained through the end of the month. The wettest days were the 26 th, the 30 th and 31 st. On the 26 th, Williams had 0.90, Payson had 0.76, Navajo National Monument had 0.50, Grand Canyon North Rim had 0.36, Canyon de Chelly had 0.34, Cottonwood had 0.25, and St. Johns had 0.83. On the 30 th and 31 st, Show Low totaled 0.85, Lost Dutchman State Park at Apache Junction had 0.87, Winslow had 0.64, Phoenix Airport had 0.13, and Grand Canyon Airport had 0.85. The month was characterized by highly localized storm activity, and most of the storms were relatively fast moving or short-lived, so rainfall totals were generally not high. However, the CoCoRaHS network (www.cocorahs.org) and the Rainlog network (www.rainlog.org) have denser rain gage coverage, so there were likely some higher daily rainfall totals that are reported here with the Airport and NOAA Cooperative network. The monthly rainfall maps below do include the CoCoRaHS data. 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 480-965-6265 Edited by Nancy J. Selover 2015 Arizona State Climate Office 1

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; 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, can be downloaded directly from the State Climate website. See p.19 of this report for calendar abbreviations. August 2015 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2

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FLAGSTAFF CLIMATE STATISTICS August 2015 This August had no significant ranking for temperature or precipitation. Avg Max Temp (F) 79.8 Normal 78.4 Avg Min Temp (F) 51.3 Normal 50.1 Avg Mean Temp (F) 65.6 Normal 64.2 Departure from Normal (F) +1.4 Highest Monthly Avg Temp (F) 67.5 in 1944 Lowest Monthly Avg Temp (F) 59.5 in 1968 Highest Temp this month (F): 87 on 16 th Lowest Temp this month (F): 47 on 3 rd, 28 th, 29 th Record High (F): 93 on 8/02/1902 Record Low (F): 24 on 8/23/1968 Temperature or precipitation records this month: 7 th Precip 1.57 set, previous record 1.14 in 1937 11 th HiMin 57 tied, first set in 2006 Flagstaff Number of Days of: Minimum Temp 55 o F or higher 4 Minimum Temp 50 o F or lower 14 Maximum Temp 85 o F or higher 5 Maximum Temp 75 o F or lower 7 Heating Degree Days 14 Normal 56 Cooling Degree Days 39 Normal 33 Degree base 65 o F Total August Precipitation 3.02 Normal August Precipitation 3.11 Departure from normal -0.09 Greatest 24-Hr Precipitation 1.60 on 7 th -8 th Total Precipitation Year-to-Date 18.42 Departure from Normal +4.23 Number of Days: Clear 21 Partly Cloudy 10 Cloudy 0 Greatest August Precipitation 8.77 in 1904 Least August Precipitation 0.26 in 1962 Average Wind Speed Highest Peak Gust 4.9 mph 36 mph from 200 o on 7 th PHOENIX CLIMATE STATISTICS August 2015 This August was the second warmest and had no significant ranking for precipitation. Avg Max Temp(F) 107.7 Normal 104.4 Avg Min Temp(F) 85.6 Normal 82.7 Avg Mean Temp (F) 96.6 Normal 93.6 Departure from Normal (F) +3.0 Highest Monthly Avg Temp (F) 98.3 in 2011 Lowest Monthly Avg Temp (F) 84.6 in 1918 Highest Temp this month (F): Lowest Temp this month (F): 117 on 14 th 76 on 11 th Record High (F): 117 on 8/14/2015, 8/26/2011 Record Low (F): 58 on 8/20/1917 Temperature or precipitation records this month: 6 th HiMin 92 set, previous record 91 in 2009 14 th HiMax 117 set, previous record 113 in 1988 14 th HiMin 93 set, previous record 92 in 2012 15 th HiMax 115 set, previous record 112 in 1992 15 th HiMin 93 set, previous record 90 in 2010 16 th HiMin 93 set, previous record 91 in 2013 17 th HiMin 91 tied, first set in1992 20 th HiMin 88 tied, first set in 2007 Phoenix Number of Days of: Minimum Temp 80 o F or lower 7 Minimum Temp 90 o F or higher 4 Maximum Temp 100 o F or lower 2 Maximum Temp 110 o F or higher 8 Heating Degree Days 0 Normal 0 Cooling Degree Days 989 Normal 885 Degree base 65 o F 4

Total August Precipitation 1.29 Normal August Precipitation 1.00 Departure from normal +0.29 Greatest 24-Hr Precipitation 0.72 7/31 to 8/1 Total Precipitation Year-to-Date 5.17 Departure from Normal -0.11 Greatest August Precipitation 5.33 in 1951 Least August Precipitation 0.00 in 1973, 1975, and 2002 Average Wind Speed 7.1 mph Highest Peak Gust 61 mph from 310 o on 31 st Number of Days: Clear 8 Partly Cloudy 23 Cloudy 0 TUCSON CLIMATE STATISTICS August 2015 This August was the third warmest and had no significant ranking for precipitation. Avg Max Temp(F) 101.4 Normal 97.4 Avg Min Temp(F) 76.6 Normal 73.3 Avg Mean Temp(F) 89.0 Normal 85.3 Departure from Normal (F) +3.7 Highest Monthly Avg Temp (F) 90.2 in 1994 Lowest Monthly Avg Temp (F) 80.8 in 1923 Heating Degree Days 0 Normal 0 Cooling Degree Days 752 Normal 631 Degree base 65 o F Total August Precipitation 1.80 Normal August Precipitation 2.39 Departure from normal -0.59 Greatest 24-Hr Precipitation 0.43 on 24-25 th Total Precipitation Year-to-Date 8.14 Departure from Normal +0.23 Highest Temp this month (F): Lowest Temp this month (F): 110 on 15 th 72 on 13 th and 25 th Greatest August Precipitation 7.93 in 1955 Least August Precipitation 0.08 in 1924 Record High (F): 112 on 08/01/1993 Record Low (F): 55 on 08/20/1917 Temperature or precipitation records this month 14 th HiMax 107 set, previous record 106 in 1994 15 th HiMax 110 set, previous record 109 in 1915 16 th HiMin 84 set, previous record 82 in 2013 17 th HiMin 80 tied, first set in 1951 20 th HiMin 80 tied, first set in 2010 Tucson Number of Days of: Minimum Temp 75 o F or lower 14 Minimum Temp 80 o F or higher 5 Maximum Temp 95 o F or lower 2 Maximum Temp 105 o F or higher 7 Number of Days: Clear 27 Partly Cloudy 0 Cloudy 0 Average Wind Speed Highest Peak Gust 7.4 mph 54 mph from 180 o on 8 th Data are from the National Weather Service and the National Climatic Data Center and are preliminary. 5

Wind Speeds for May: Day Phoenix Flagstaff Tucson (mph) Avg Max Avg Max Avg Max 1 5.3 15 2.7 15 8.6 44 2 8.1 28 4.4 30 6.7 19 3 6.8 23 4.9 25 5.7 20 4 7.1 25 5.8 27 5.9 22 5 6.7 28 6.4 30 6.5 31 6 6 20 5.6 32 7.3 26 7 9.2 32 8.1 36 6.4 30 8 5.4 18 5.2 22 8.1 54 9 6.8 31 3.9 22 8.6 36 10 6 24 3.5 24 5.2 22 11 7.6 51 4.9 25 9.8 43 12 5.5 27 5 23 7.6 45 13 5.6 17 2.3 17 7.2 21 14 6.8 28 3 23 5.7 32 15 5.3 17 2.6 25 5.9 21 16 9.4 26 4.2 25 9.2 26 17 11.1 27 7.8 27 8.8 27 18 8.3 24 7.5 32 7.4 26 19 7.1 21 7.3 29 5.4 20 20 6.9 24 7.1 27 8 35 21 7.6 20 8.1 29 7.3 23 22 7.6 20 6.5 27 9.2 39 23 6.4 30 3.4 26 6.8 32 24 6.9 23 3.9 23 10.1 38 25 7.5 44 6.2 30 5.8 28 26 6.6 23 3.7 20 8 28 27 6.9 52 2.8 27 8 38 28 4.5 14 2.4 21 3.9 20 29 6.4 42 3.7 24 8.3 31 30 8.5 33 5.9 30 8.7 26 31 9 61 4 25 8.9 33 Dew Points for May: Daily Average Dew Point ( o F): Day Phx Tuc Flg 1 60 60 52 2 55 58 48 3 49 56 42 4 46 51 35 5 55 56 36 6 57 59 47 7 63 62 54 8 65 63 53 9 61 64 52 10 62 62 55 11 61 61 55 12 60 58 52 13 57 57 51 14 54 54 52 15 57 57 50 16 59 60 50 17 55 59 48 18 54 56 42 19 58 61 44 20 62 60 46 21 61 63 47 22 60 58 48 23 59 60 46 24 63 65 51 25 61 62 53 26 63 61 53 27 61 59 51 28 62 57 49 29 61 57 51 30 62 60 53 31 61 59 55 6

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The lowest minimum temperatures ranged from 28 o F at Sunrise Mountain to 81 o F at Yuma. The lowest maximum temperature of 71 o F was recorded at Snowslide Canyon, while the highest maximum temperature of 118 o F was reported at Yuma and Bullhead City. The lowest rainfall amount was 0.00 at several stations in Arizona and the highest was 7.53 at Sonoita. The lowest average dew point was 45 o F at Flagstaff and the highest was 64 o F at Paloma. The highest peak wind gust was 67 mph at Coolidge. 8

T August 2015 The highest average minimum temperature was 87 o F at Yuma and the lowest average minimum temperature was 45 o F at Sunrise Mountain. The highest average maximum temperature was 113 o F at Bullhead City and lowest average maximum temperature was 65 o F at Snowslide Canyon. 9

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August minimum temperatures were generally 0 to 3 o F warmer than average across most of the state with even warmer conditions in the southwest. Southern Gila County was cooler than average, but the bullseye at 15 degrees cooler than average is most likely an error. Daytime temperatures were 2 to 6 o F warmer than average in the southern half of the state. August precipitation was highly localized across the state with the lower Colorado River below 5% of average and much of the southwest below 50% of average. The wet areas were the Colorado Plateau, northwestern Arizona and parts of Pinal, Cochise, and Graham counties. 11

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Calendar Year 2015 Calendar year minimum temperatures have been generally 0 to 3 o F warmer than average across most of the state, with the warmest conditions in northern Gila County, and cooler than normal conditions in Graham County. Daytime temperatures have been 1 to 2 o F warmer than average across the northwest half of the state, and only slightly warmer than average across the eastern counties. This is partly due to the monsoonal precipitation patterns, which have favored the eastern part of Arizona. Cooler than normal areas include Graham and Gila counties. Precipitation continues to be variable across the state, with wetter conditions on the Colorado Plateau and southeastern Arizona as well as La Paz and northern Mohave counties. Western Maricopa Pinal and Pima counties are drier than normal 13

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2015 Water Year The water year minimum temperatures are 0 to3 o F warmer than average statewide, with the southeast near average. Daytime temperatures have been 1.5 to 3 o F warmer than average across northern Arizona and the western counties. Southeastern Arizona has been 0.5 to 1.5 o F warmer than normal, with cool pockets in western Pinal County and along the Gila-Pinal-Graham County boundary. Precipitation has been well below average in central Arizona, including Maricopa, Gila and southern Mohave counties. The Colorado Plateau has received 120 to 200% of normal precipitation, mostly due to the monsoon. 15

August Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2015: 16

August Mean Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2015: 17

2015 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff is 4.23 wetter than normal, Tucson is 0.23 wetter than normal and Phoenix is 0.11 drier than normal. 18

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) 19