Arizona Climate Summary November 2017 Summary of conditions for October 2017 October 2017 Temperature and Precipitation Summary October 1 st 18 th : A low pressure system from the northwestern U.S. moved across the state in the last couple days of September, bringing a little rainfall to Window Rock and northeastern Arizona, but otherwise leaving the state dry as the monsoon had an early end in mid-september. The first 4 days of October were dry with temperatures barely reaching 100 o F in the southwest deserts. On the 5 th, another low pressure system moved across Utah, and Window Rock again received light rain, (0.21 ), but the rest of the state remained dry. While the temperatures remaining below 100 o F provided welcome relief from the heat, much of the state was still 6 to 12 degrees warmer than normal for this time of the year. The dry conditions that followed through the rest of the month have led to a second fire season in many parts of the state as the grasses dried out after the monsoon ended early. While the circulation bounced back and forth between high and low pressure, there was no moisture in the state to produce clouds or rainfall through the 18 th of the month. Temperatures in the southwest deserts remained in the mid to upper 90s, and the higher elevations were in the mid to upper 60s. Nighttime temperatures at the highest elevations had already dipped well below freezing into the low 20s and even the teens in places like Bellemont and Window Rock. The southwest deserts saw nighttime temperatures in the upper 60s to lower 70s. Two more 100+ degree days were reported on the 16 th (101 o F) and 18 th (100 o F) at Organ Pipe National Monument, while Bartlett Dam and Glendale Airport reported 102 o F. October 19 th 31 st : A little moisture moved into the state along with a low pressure system on the 19 th, bringing 0.02 of rain to Prescott, and 0.01 to Winslow, Window Rock, Petrified Forest and the Grand Canyon Airport. The rest of the state remained dry. Temperatures remained 5 to 12 degrees warmer than normal across the state through the 29 th as a strong high pressure ridge set up over the southwest, forcing storm systems to stay well to the north, as a very deep trough moved down in to the southeastern U.S. Two small low pressure systems moved into Arizona on the 30 th and 31 st, but little moisture was associated with the systems, so precipitation was very light. The highest rainfall was 0.22 at Nogales The systems did bring temperatures back down to seasonal normals in time for Halloween. In This Issue: Overview of October, graphs of the October daily maximum and minimum temperatures, precipitation, mean daily dew points for Flagstaff, Phoenix, and Tucson; October climate statistics, maps of mean monthly maximum and minimum temperatures, precipitation, dew points, wind speeds for October; and graphs of the mean October 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.19 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 2017 Arizona State Climate Office 1
October 2017 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2
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FLAGSTAFF CLIMATE STATISTICS October 2017 This October was tied for 20 th warmest with 4 other years and was tied for driest October with 8 other years. Avg Max Temp (F) 68.1 Normal 62.0 Avg Min Temp (F) 31.6 Normal 31.5 Avg Mean Temp (F) 49.9 Normal 46.8 Departure from Normal (F) -+3.1 Highest Monthly Avg Temp (F) 52.5 in 1988 Lowest Monthly Avg Temp (F) 38.6 in 1971 Highest Temp this month (F): 75 on 7 th Lowest Temp this month (F): 23 on 7 th Record High (F): 85 on 10/1/1980 Record Low (F): -2 on 10/30/1971 Temperature or precipitation records this month: 24 th HiMin 46 set, previous record 43 in 1960 Flagstaff Number of Days of: Minimum Temp 40 o F or higher 1 Minimum Temp 30 o F or lower 14 Maximum Temp 70 o F or higher 12 Maximum Temp 60 o F or lower 2 Heating Degree Days 462 Normal 566 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total October Precipitation 0.00 Normal October Precipitation 1.66 Departure from normal -1.66 Greatest 24-Hr Precipitation 0.00 Total Precipitation Year-to-Date 18.00 Departure from Normal -0.23 Total October Snowfall 0.0 Normal Trace Record October Snowfall 24.7 in 1971 Number of Days: Clear 31 Partly Cloudy 0 Cloudy 0 Greatest October Precipitation 9.86 in 1972 Least October Precipitation: 0.00 in 1917, 1902, and six other years. Average Wind Speed Highest Peak Gust 7.4 mph 45 mph from 220 o on 20 th PHOENIX CLIMATE STATISTICS October 2017 This October was the 5 th warmest and was tied for driest with 21 other years. Avg Max Temp(F) 93.8 Normal 88.5 Avg Min Temp(F) 67.1 Normal 64.8 Avg Mean Temp (F) 80.5 Normal 76.7 Departure from Normal (F) +3.8. Highest Monthly Avg Temp (F) 82.7 in 2003 Lowest Monthly Avg Temp (F) 66.1 in 1916 Highest Temp this month (F) 99 on 24 th, 16 th, 4 th Lowest Temp this month (F): 61 on 27 th, 22 nd Record High (F): 107 on 10/1-2/1980 Record Low (F): 34 on 10/30/1971 4 Temperature or precipitation records this month: 17 th HiMin 72 tied, first set in 2009 19 th HiMin 74 set, previous record 73 in 1988 24 th HiMax 99 set, previous record 97 in 1933 25 th HiMin 71 tied, first set in 2011 Phoenix Number of Days of: Minimum Temp 65 o F or lower 10 Minimum Temp 70 o F or higher 7 Maximum Temp 90 o F or lower 5 Maximum Temp 95 o F or higher 15 Heating Degree Days 0 Normal 6 Cooling Degree Days 490 Normal 367 Degree base 65 o F Total October Precipitation 0.00 Normal October Precipitation 0.58
Departure from normal -0.58 Greatest 24-Hr Precipitation 0.00 Total Precipitation Year-to-Date 4.73 Departure from Normal -1.77 Greatest October Precipitation 4.40 in 1972 Least October Precipitation 0.00 in 1999,1995 and 19 other years Number of Days: Clear 24 Partly Cloudy 7 Cloudy 0 Average Wind Speed 5.3 mph Highest Peak Gust 31 mph from 070 o on 24 th TUCSON CLIMATE STATISTICS October 2017 This October was the 2 nd warmest and tied for driest with 19 other years. Avg Max Temp(F) 92.5 Normal 84.8 Avg Min Temp(F) 62.1 Normal 57.3 Avg Mean Temp(F) 77.3 Normal 71.0 Departure from Normal (F) +6.3 Highest Monthly Avg Temp (F) 77.5 in 2016 Lowest Monthly Avg Temp (F) 63.1 in 1920 Highest Temp this month (F): 99 on 4 th and 5 th Lowest Temp this month (F): 55 on 22 nd, 24 th, 28 th Record High (F): 102 on 10/01/2010, 10/3/1993 Record Low (F): 26 on 10/30/1971 Temperature or precipitation records this month: 11 th HiMin 68 tied, first set in 1958 16 th HiMin 71 set, previous record 69 in 1977 17 th HiMin 70 set, previous record 69 in 1955 23 rd HiMax 96 set, previous record 94 in 1933 25 th HiMin 68 set, previous record 66 in 2015 25 th HiMax 95 tied, first set in 2014 Tucson Number of Days of: Minimum Temp 60 o F or lower 16 Minimum Temp 70 o F or higher 4 Maximum Temp 90 o F or lower 8 Maximum Temp 95 o F or higher 12 Heating Degree Days 0 Normal 0 Cooling Degree Days 389 Normal 212 Degree base 65 o F Total October Precipitation 0.00 Normal October Precipitation 0.89 Departure from normal -0.89 Greatest 24-Hr Precipitation 0.00 Total Precipitation Year-to-Date 10.18 Departure from Normal +0.09 Greatest October Precipitation 4.98 in 2000 Least October Precipitation 0.00 in 2013, 1982, 1973, and 17 other years Number of Days: Clear 29 Partly Cloudy 0 Cloudy 0 Average Wind Speed Highest Peak Gust 7.4 mph 39 mph from 120 o on 25 th Data are from the National Weather Service and the National Climatic Data Center and are preliminary. 5
Wind Speeds for October: Day Phoenix Flagstaff Tucson (mph) Avg Max Avg Max Avg Max 1 6.9 23 13.2 40 7.5 28 2 6.6 20 13.6 44 8.1 34 3 6.9 24 7.7 35 6.7 30 4 4.8 21 9.5 34 5.2 20 5 5.3 22 8.6 32 5.1 20 6 5.2 19 4 23 7.1 26 7 3.2 15 3.9 20 6.3 17 8 6.6 17 11.7 42 8.8 26 9 6.2 28 13.6 34 7 27 10 5.4 24 7.3 24 8.9 32 11 5.4 20 8.8 37 10.7 29 12 5.3 16 10.7 37 7.5 21 13 4.6 24 7.8 34 5.8 26 14 4.2 17 7.7 23 6.5 25 15 3.6 18 6.2 20 5.9 26 16 5.4 20 2.4 21 12 38 17 3 15 2.3 23 7.5 24 18 4.5 19 4.1 22 5.5 26 19 6.4 20 5.5 29 7.3 23 20 9.9 27 16.2 45 8.1 30 21 4.6 14 3.4 18 4.1 20 22 3.5 16 3 16 5.3 19 23 3.9 12 7.5 25 6.6 19 24 7.6 31 13 31 12.1 36 25 6.8 21 4 20 12.3 39 26 5.2 23 5.3 25 7.7 24 27 4 20 6.4 22 5.9 22 28 4.8 20 5 25 6.2 19 29 4.8 15 4.4 22 5.9 17 30 5.7 16 6 22 8.6 29 31 4.8 20 6.6 24 5.8 20 Dew Points for October: Daily Average Dew Point ( o F): Day Phx Tuc Flg 1 38 27 32 2 39 32 27 3 42 41 32 4 40 44 28 5 36 38 15 6 26 23 15 7 22 15 10 8 28 33 12 9 22 27 13 10 33 38 19 11 36 42 20 12 34 37 24 13 36 32 17 14 29 30 5 15 34 34 10 16 38 40 15 17 44 41 23 18 43 38 27 19 41 37 29 20 44 40 24 21 34 36 20 22 33 27 14 23 29 23 19 24 34 30 17 25 35 29 14 26 33 28 21 27 31 25 16 28 32 24 19 29 35 30 22 30 44 37 29 31 39 36 26 6
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October 2017 The minimum temperatures ranged from 6 o F at Fort Valley to 63 o F at Litchfield Park. The lowest maximum temperature of 63 o F was recorded at Snowslide Canyon and the highest was 102 o F at Bartlett Dam and Glendale AP. The highest rainfall totals were 0.87 at Portal, and 0.86 at Catalina State Park.. The lowest average dew point was 17 o F at Grand Canyon National Park and the highest was 44 o F at Paloma. The highest peak wind gusts were 41 mph at Mohave 2, and 40 at Mohave and Ft. Mohave. Average wind speeds ranged from 2 mph in the Phoenix area to 16 mph at Laughlin-Bullhead City Airport. 8
T October 2017 The highest average minimum temperature was 70 o F at Yuma, and the lowest average minimum temperature was 23 o F at Fort Valley. The highest average maximum temperature was 97 o F at Tacna and the lowest average maximum temperature was 58 o F at Snowslide Canyon. 9
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October October minimum temperatures were 2 to 6 o F warmer than normal in south central Arizona, 0 to 4 o F cooler than normal in northeastern and northwestern Arizona, and within 2 o F of normal in the rest of the state. Daytime temperatures were 2 to 8 o F warmer than normal across the state. Virtually the entire state received less than 25% of normal October precipitation. 11
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Calendar Year 2017 Nighttime temperatures were 1 to 3 o F warmer than average across most of the state with cooler than normal pockets in La Paz, Cochise, Graham, northern Gila, northern Mohave and western Pima counties. Daytime temperatures were 1 to 3 o F warmer than normal across most of the state with slightly cooler than normal areas in western Pinal, southern Gila, southern Navajo, and northwestern Maricopa counties. Some areas of Apache, Navajo, Pima and Cochise counties were 3-4 o F warmer than normal. Northern and central Arizona have been wetter than normal with the exception of southern Navajo and Apache counties. Southern Arizona and Navajo and Apache counties received 70-90% of normal precipitation, while central and northern Arizona received 90 to 150% of normal rainfall since January 1st. 13
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s aham, Cochise, La Paz, OPima and 2018 Water Year Water Year 2018 minimum temperatures were 2 to 6 o F warmer than normal in south central Arizona, 0 to 4 o F cooler than normal in northeastern and north western Arizona, and within 2 o F of normal in the rest of the state. Daytime temperatures were 2 to 8 o F warmer than normal across the state. Virtually the entire state received less than 25% of normal precipitation at the start of the new Water Year. 15
October Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2017: 16
October Mean Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2017 17
2017 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff is 0.23 below normal, Tucson is 0.09 above normal, and Phoenix is 1.77 below 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