Arizona Climate Summary January 2017 Summary of conditions for December 2016 December 2016 Temperature and Precipitation Summary December 1 st 15 th : Similar to November, December began with a dry trough of low pressure over the western US. Cold arctic air extended into Arizona and New Mexico keeping temperatures below normal across the state for the first week of the month. A cut-off low pressure system brought some moisture into Arizona on the 2 nd and 3 rd, but only Bellemont received any precipitation (0.02 ). By the 5 th, the system had moved east and the cold air retreated northward. By the 9 th, temperatures had warmed to above average and remained warmer than normal through the 16 th. The warm and dry conditions were due to a zonal flow that brought dry, warm air from the subtropical Pacific Ocean. Several storm systems moved across the Pacific Northwest and into Utah and Colorado. These storms dumped much needed snowfall in the Sierra, Wasatch and Rocky Mountains. High pressure briefly set up over the southwest on the 14 th and 15 th, raising temperatures into the low 80s in the southwest deserts and into the 50s at the higher elevations. The coldest nighttime lows went from single digits in the first week of the month to near freezing by the 16 th. December 16 th 31 st : By the 16 th the high pressure ridge broke down and a strong cold front moved across California into Arizona. The storm was relatively warm, but was followed by very cold air. Precipitation was light to moderate and snow levels were high. Precipitation totals included 1.05 at Flagstaff, 0.22 at the Grand Canyon, 0.09 at Deer Valley Airport, 0.10 at Phoenix Sky Harbor, 0.35 at Valle, 0.59 at Window Rock, 0.69 at Alpine, 1.46 at Bellemont, 0.17 at Coronado National Monument, 0.01 at Tucson Airport, 1.35 at Payson, 0.09 at Petrified Forest, 0.97 at Prescott, 0.41 at Seligman, 1.22 at Show Low, 0.50 at Springerville, and 0.56 at Williams. Behind the front temperatures dropped, plunging nighttime lows back to the single digits at the higher elevations, with milder conditions in the southwest deserts. Another pair of low pressure systems moved into the state late on the 21 st and remained through the 25 th. This system was colder and brought a white Christmas to the higher elevations in the state. Snowfall totals included 21.9 at Flagstaff Airport, 11.7 at Bellemont, 1.5 at Prescott, 5.1 at Payson, 0.5 at Seligman, and 2.0 at Show Low. Rain at the lower elevations included 0.80 at Youngtown, 0.69 at Petrified Forest, 1.01 at Lost Dutchman State Park, 0.88 at Eloy, 0.19 at Coronado National Monument, 0.52 at Carefree, 1.26 at Canyon de Chelly, 0.80 at Bullhead City, 0.75 at Yuma, 0.53 at Tucson Airport, 0.76 at Sonora Desert Museum, 0.65 at Phoenix Airport, 1.08 at Kingman, 0.82 at Bisbee-Douglas Airport, 1.76 at Douglas, and 0.94 at Nogales. The low pressure system cut off on the 26 th and temperatures plummeted back down to single digits and negative values in places like Grand Canyon, Alpine, Bellemont and Flagstaff. Daytime highs in the deserts hovered in the mid- to upper-70s until the 31 st when another storm system brought more rain and snow to the state. New Year s Eve precipitation was under an inch statewide in terms of rain or melted snow. Navajo National Monument had 3.5 of snow on New Year s Eve, while Bellemont had 0.7. Total precipitation for the month was above normal in northwest and north central Arizona as well as in the southwest. The northeast was drier than normal. Flagstaff and Tucson finished the calendar year wetter than normal, while Phoenix was drier than normal. In This Issue: Overview of December, graphs of the December daily maximum and minimum temperatures, precipitation, mean daily dew points for Flagstaff, Phoenix, and Tucson; December climate statistics, maps of mean monthly maximum and minimum temperatures, precipitation, dew points, wind speeds for December; and graphs of the mean December 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. Data are preliminary and are from the National Weather Service Forecast Offices in Flagstaff, Phoenix and Tucson. Dr. Nancy J. Selover, State Climatologist http://azclimate.asu.edu 480-965-6265 Edited by Nancy J. Selover 2017 Arizona State Climate Office 1
**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. December 2016 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2
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FLAGSTAFF CLIMATE STATISTICS December 2016 This December had no significant ranking for temperature and was the 12 th wettest on record. 2016 was tied for 16 th warmest year with 1980, and was the 19 th wettest year. Avg Max Temp (F) 43.9 Normal 42.5 Avg Min Temp (F) 20.9 Normal 16.8 Avg Mean Temp (F) 32.4 Normal 29.9 Departure from Normal (F) +2.8 Highest Monthly Avg Temp (F) 39.8 in 1980 Lowest Monthly Avg Temp (F) 21.9 in 1972, 1932 Highest Temp this month (F): 57 on 14 th Lowest Temp this month (F): 0 on 26 th Record High (F): 68 on 12/11/1950 Record Low (F): -23 on 12/23/1990, 12/08/1978 Temperature or precipitation records this month: 24 th Precip 1.16 set, previous record 0.44 in 1959 24 th Snow 10.1 set, previous record 4.0 in 1914 Flagstaff Number of Days of: Minimum Temp 30 o F or higher 5 Minimum Temp 15 o F or lower 9 Maximum Temp 50 o F or higher 10 Maximum Temp 40 o F or lower 9 Heating Degree Days 1003 Normal 1096 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total December Precipitation 4.42 Normal December Precipitation 1.87 Departure from normal +2.55 Greatest 24-Hr Precipitation 1.64 on 12/24-25 Total Precipitation Year-to-Date 25.80 Departure from Normal +3.94 Total December Snowfall 15.0 Normal 16.9 Record December Snowfall 86.0 1967 Number of Days: Clear 20 Partly Cloudy 5 Cloudy 6 Greatest December Precipitation 7.30 in 1967 Least December Precipitation: 0.00 in 1917, 1958, and 1999. Average Wind Speed Highest Peak Gust 7.4 mph 64 mph from 210 o on 16 th PHOENIX CLIMATE STATISTICS December 2016 This December was the 6 th warmest and had no significant ranking for precipitation. 2016 was tied for 3 rd warmest with 2012 and 2015, and had no significant ranking for annual precipitation. Avg Max Temp(F) 68.4 Normal 66.0 Avg Min Temp(F) 47.4 Normal 44.8 Avg Mean Temp (F) 57.9 Normal 55.4 Departure from Normal (F) +2.5 Highest Monthly Avg Temp (F) 61.3 in 1980 Lowest Monthly Avg Temp (F) 46.6 in 1911 Highest Temp this month (F) Lowest Temp this month (F): 77 on 29 th 38 on 26 th & 18 th 4 Record High (F): 87 on 12/10/1950 Record Low (F): 22 on 12/26/1911, 12/31/1900 Temperature or precipitation records this month: 13 th HiMin 58 set, previous record 57 in 1934 16 th HiMin 57 set, previous record 55 in 1991 21 st HiMin 59 set, previous record 57 in 2010 Phoenix Number of Days of: Minimum Temp 40 o F or lower 3 Minimum Temp 50 o F or higher 12 Maximum Temp 65 o F or lower 10 Maximum Temp 75 o F or higher 4 Heating Degree Days 211 Normal 298 Cooling Degree Days 1 Normal 1 Degree base 65 o F
Total December Precipitation 0.95 Normal December Precipitation 0.88 Departure from normal +0.07 Greatest 24-Hr Precipitation 0.42 on 21-22 Total Precipitation Year-to-Date 6.19 Departure from Normal -1.84 Greatest December Precipitation 3.98 in 1967 Least December Precipitation 0.00 in 1981, 2000, and 1999 and 14 other years. Number of Days: Clear 7 Partly Cloudy 20 Cloudy 4 Average Wind Speed 4.9 mph Highest Peak Gust 48 mph from 270 o on 24 th TUCSON CLIMATE STATISTICS December 2016 This December was tied for 5 th warmest, along with 1939 and 1940 and had no significant ranking for precipitation. 2016 was tied with 2014 as the hottest year on record, and had no significant ranking for annual precipitation. Avg Max Temp(F) 69.1 Normal 64.8 Avg Min Temp(F) 43.4 Normal 39.1 Avg Mean Temp(F) 56.3 Normal 51.9 Departure from Normal (F) +4.4 Highest Monthly Avg Temp (F) 41.3 in 1915 Lowest Monthly Avg Temp (F) 58.1 in 1980 Highest Temp this month (F): 84 on 15 th Lowest Temp this month (F): 28 on 18 th Record High (F): 85 on 11/08/1939, 12/29/1921, 12/02/1911 Record Low (F): 10 on 12/14/1901 Temperature and precipitation records this month: 15 th HiMax 84 set, previous record 81 in 1969 16 th HiMin 57 set, previous record 56 in 1980 21 st HiMin 54 set, previous record 53 in 2010 31 st HiMin 51 set, previous record 50 in 1929 Heating Degree Days 264 Normal 405 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total December Precipitation 1.08 Normal December Precipitation 0.93 Departure from normal +0.15 Greatest 24-Hr Precipitation 0.35 on 30-31 Total Precipitation Year-to-Date 11.81 Departure from Normal +0.22 Greatest December Precipitation 5.85 in 1914 Least December Precipitation: 0.00 in 1981, 1973, 1958 and 8 other years. Number of Days: Clear 16 Partly Cloudy 6 Cloudy 2 Average Wind Speed Highest Peak Gust 6.5 mph 48 mph from 230 o on 24 th Data are from the National Weather Service and the National Climatic Data Center and are preliminary. Tucson Number of Days of: Minimum Temp 40 o F or lower 10 Minimum Temp 50 o F or higher 6 Maximum Temp 65 o F or lower 10 Maximum Temp 75 o F or higher 8 5
Wind Speeds for December: Day Phoenix Flagstaff Tucson (mph) Avg Max Avg Max Avg Max 1 5 12 0.6 11 5.6 18 2 5.8 20 9.7 29 6.4 25 3 4.7 17 17.9 39 5.6 20 4 2.3 17 6.9 32 5.1 16 5 4.8 19 5.3 20 6.8 19 6 5.3 17 15.4 38 6.7 25 7 5.1 17 4.7 28 3.7 16 8 2.4 13 4 18 4.7 13 9 3.3 15 3 16 4.9 13 10 3.2 11 6.9 27 5.5 14 11 4.1 11 5.9 22 5.2 16 12 3.8 14 5.2 27 5.7 17 13 4 M 6.5 28 5.7 20 14 3.4 14 4.5 24 5.8 17 15 4.5 17 12.6 50 6.2 16 16 8.5 30 24 64 10.4 29 17 11.4 37 9.4 52 9.5 43 18 4.1 18 7 26 4.7 14 19 6.4 30 7.4 22 10.1 31 20 4.7 22 2 11 8.1 22 21 6.9 18 4.2 19 5.7 26 22 8.8 26 9.9 33 8.4 30 23 3 14 10.4 22 3.3 16 24 9.3 48 15.4 52 13.1 48 25 5.2 18 10.7 39 5 19 26 3.5 15 2.6 16 4.8 21 27 1.8 14 1.5 10 4.2 20 28 2.2 14 2.6 12 3.4 14 29 3.8 15 4.9 22 12.1 40 30 6.9 23 3.4 15 10.6 33 31 4.9 18 6.3 20 3.1 20 Dew Points for December: Daily Average Dew Point ( o F): Day Phx Tuc Flg 1 29 17 16 2 27 23 16 3 24 24 8 4 26 23 12 5 27 27 17 6 37 34 24 7 40 35 21 8 39 34 24 9 39 33 26 10 39 32 31 11 40 34 31 12 42 36 31 13 43 36 30 14 42 30 28 15 51 34 37 16 32 32 20 17 32 31 20 18 23 28 8 19 28 28 11 20 37 42 20 21 51 49 32 22 51 48 35 23 49 42 32 24 40 37 21 25 35 34 16 26 35 36 16 27 39 41 16 28 41 44 21 29 42 44 21 30 38 44 20 31 53 52 34 6
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The minimum temperatures ranged from -9 o F at Sunrise Mountain to 48 o F at Parker. The lowest maximum temperature of 36 o F was recorded at Mount Logan, while the highest maximum temperature was 86 o F at Chandler Airport. The highest rainfall amounts were 15.90 at Parker and 10.12 at Bullhead City. The lowest average dew point was 20 o F at Page and the highest was 42 o F at Buckeye. The highest peak wind gust was 54 mph at Safford. Average wind speeds ranged from 2 mph at central Phoenix, Mesa and Payson to 16 mph at Laughlin-Bullhead City. 8
T December 2016 The highest average minimum temperature was 50 o F at Yuma, and the lowest average minimum temperature was 15 o F at Sunset Crater. The highest average maximum temperature was 73 o F at Organ Pipe Cactus National Monument and lowest average maximum temperature was 23 o F at Mount Logan. 9
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December December minimum temperatures were 2 to 6 o F warmer than average across most of the state, and 6 to 8 o F warmer than normal in Greenlee and Gila counties. Western Pima County and most of Mohave County were only 0 to 2 o F warmer than normal. Daytime temperatures were within 1 o F of normal in the western counties, 1 to 4 o F warmer than normal in central and eastern Arizona, and 4 to 6 o F warmer than normal in Apache and Navajo counties. Almost all of Arizona was wetter than normal in December. Central and western Arizona had more than 150% of normal precipitation, while southeastern Arizona had 100% of normal. Western Pima County received just under 100% of normal while northern Apache and Navajo counties received less than 25% of normal December precipitation. 11
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Calendar Year 2016 Calendar year minimum temperatures have increased to 2 to 4 o F warmer than normal in Yuma, La Paz, southern Mohave, western Maricopa and northern Pinal counties, while central Gila County was 4 to 8 o F warmer than normal. Western Pima, southern Graham, and eastern Cochise counties were 0 to 2 o F cooler than normal. Daytime temperatures were 1 to 3 o F warmer than normal statewide, with slightly cooler conditions in western Pinal and northwestern Maricopa counties. Precipitation was above normal in Coconino, northern Mohave and northern La Paz counties as well as in southeastern Arizona. The northeast, southwest and central parts of the state were drier than normal. 13
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2017 Water Year The 2017 Water Year minimum temperatures are still 2 to 6 o F warmer than average across most of the state. Daytime temperatures are also 2 to 4 o F warmer than average across most of the state, with the northeast corner 4 to 6 o F warmer than normal. Southern and northeastern Arizona have received less than 70% of normal precipitation. Central and western Arizona have received over 110% of normal precipitation, with over 200% in La Paz and northwestern Coconino counties. 15
December Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2016: 16
December Mean Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2016 17
2016 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff was 3.94 above normal, Tucson was 0.22 above normal, and Phoenix was 1.84 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