Arizona Climate Summary

May 2015 Temperature and Precipitation Summary Arizona Climate Summary June 2015 Summary of conditions for May 2015 May 1 st 14 th : May began with high pressure in the west, and May 1 st was dry statewide, with high temperatures around 100 in the southwest deserts and nighttime lows below freezing at the highest elevations. On the 2 nd and 3 rd a short wave moved through the southwest bringing light rainfall to northern Arizona. By the 4 th and 5 th a low pressure system moved through bringing heavier rainfall, and dropping temperatures as much as 15 degrees below normal. Phoenix airport received 0.24 of rain, Deer Valley had 0.54, Scottsdale had 0.47, Sedona had 0.71, Window Rock had 0.27, Winslow had 0.29, Castle Hot Springs had -.55, Carefree had 1.02, Payson ad 0.25 and Pinnacle Peak had 1.45, Show Low had 0.39, and Youngtown had 0.24. This storm was followed by another that moved slowly through the southwest bringing rainfall through the 10 th. On the 9 th, Bellemont, just west of Flagstaff had 1.1 of snow. The low pressure and humidity lingered for a few more days with more light showers. The storm was relatively cold, dropping highs in the deserts into the upper 70s. Nighttime temperatures in the higher elevations dropped into the lower 20s. A third low pressure system moved very slowly down the west coast with significant moisture ahead of it that brought light scattered rainfall to many areas of the state, but no heavy rain through the 14th May 15 th 31 st : By the 15 th the strong low pressure system finally moved into Arizona with heavier rainfall, and significant snowfall at the higher elevations of northern Arizona. On the 15 th and 16 th, Flagstaff had received 0.71, Phoenix Deer Valley had 0.80, Phoenix airport had 0.93, Prescott had 1.19, Scottsdale had 1.33, Canyon de Chelly had 0.79 Carefree had 1.10, Eloy had 0.78, Apache Junction had 1.13, Payson had 1.29, Petrified Forest had 0.91, Pinnacle Peak had 1.15. Bellemont had 9.2 of snow and the north rim of the Grand Canyon had 2.0 of snow. The system was slow to move out, with light showers for two more days. The 20 th was only the fourth dry day of the month statewide. The next low pressure system began affecting the state in the 21 st, slowly increasing in intensity each day with the heaviest rainfall on the 24 th with 1.64 at Navajo National Monument and 0.90 at Canyon de Chelly. The moisture was much needed in the northeast quarter of the state. The system finally exited the state on the 27 th, and by the 29 th, high pressure finally dominated the southwest, bringing clear skies and normal temperatures. May was relatively cool across most of the state, due to the frequent storm systems. This May was the 2 nd wettest for Phoenix airport with 1.17 of rain. The wettest was 1930 with 1.31 of rain. Flagstaff had its 11 th wettest May, which brought them well above normal for this time of the calendar year. 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. In This Issue: Overview of April, graphs of the May daily maximum and minimum temperatures, precipitation, mean daily dew points for Flagstaff, Phoenix, and Tucson; May climate statistics, maps of mean monthly maximum and minimum temperatures, precipitation, dew points, wind speeds for April; and graphs of the mean May 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. 16 of this report for calendar abbreviations. Dr. Nancy J. Selover, State Climatologist http://azclimate.asu.edu 480-965-6265 Edited by Nancy J. Selover 2015 Arizona State Climate Office 1

Notice*** The National Climatic Data Center (NCDC) has changed its name to the National Center for Environmental Information (NCEI). The new website was unveiled April 21 st, http://www.ncei.noaa.gov/ There are some organizational changes at NOAA, associated with this change, but the mission of providing climate data will continue. May 2015 Daily Temperature, Precipitation, & Dew Point for Flagstaff, Phoenix, and Tucson 2

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FLAGSTAFF CLIMATE STATISTICS May 2015 This May had no significant ranking for temperature and was the 11 th wettest May on record. Avg Max Temp (F) 61.1 Normal 68.1 Avg Min Temp (F) 34.1 Normal 35.0 Avg Mean Temp (F) 47.6 Normal 51.6 Departure from Normal (F) -4.0 Highest Monthly Avg Temp (F) 56.8 in 1984 Lowest Monthly Avg Temp (F) 44.6 in 1917 Highest Temp this month (F): 80 on 31 st Lowest Temp this month (F): 25 on 9 th Record High (F): 89 on 5/31/2002 Record Low (F): 7 on 5/03/2015 Temperature or precipitation records this month: 15 th LoMax 39 set, previous record 44 in 1957 15 th Precip 0.65 set, previous record 0.52 in 1951 Flagstaff Number of Days of: Minimum Temp 40 o F or higher 6 Minimum Temp 30 o F or lower 9 Maximum Temp 70 o F or higher 6 Maximum Temp 50 o F or lower 4 Heating Degree Days 534 Normal 417 Cooling Degree Days 0 Normal 0 Degree base 65 o F Total May Precipitation 1.80 Normal May Precipitation 0.63 Departure from normal +1.17 Greatest 24-Hr Precipitation 0.66 on 14 th -15 th Total Precipitation Year-to-Date 10.93 Departure from Normal +2.82 Number of Days: Clear 18 Partly Cloudy 11 Cloudy 2 Greatest May Precipitation 4.14 in 1992 Least May Precipitation 0.00 in 2012, 2004, 2002 Average Wind Speed Highest Peak Gust 7.3 mph 49 mph from 210 o on 14 th PHOENIX CLIMATE STATISTICS May 2015 This May had no significant temperature ranking and was the second wettest May on record. Avg Max Temp(F) 90.1 Normal 94.8 Avg Min Temp(F) 67.4 Normal 69.4 Avg Mean Temp (F) 78.7 Normal 82.1 Departure from Normal (F) -6.6 Highest Monthly Avg Temp (F) 87 in 1984 Lowest Monthly Avg Temp (F) 69 in 1917 Highest Temp this month (F): 107 on 31 st Lowest Temp this month (F): 57 on 16 th,15 th,9th Record High (F): 114 on 5/30/1910 Record Low (F): 39 on 5/03/1899 Temperature or precipitation records this month: 15 th HiPCP 0.93 set, previous record 0.70 in 1953 Phoenix Number of Days of: Minimum Temp 65 o F or lower 11 Minimum Temp 70 o F or higher 12 Maximum Temp 80 o F or lower 4 Maximum Temp 90 o F or higher 17 Heating Degree Days 0 Normal 0 Cooling Degree Days 435 Normal 531 Degree base 65 o F Total May Precipitation 1.17 Normal May Precipitation 0.11 Departure from normal 1.06 Greatest 24-Hr Precipitation 0.93 5/15 Total Precipitation Year-to-Date 2.50 4

Departure from Normal -1.77 Number of Days: Clear 11 Partly Cloudy 19 Cloudy 1 Least May Precipitation 0.00 in 2014, 2013, 2010, and 57 other years Average Wind Speed 7.4 mph Highest Peak Gust 39 mph from 210 o on 3 rd Greatest May Precipitation 1.31 in 1930 TUCSON CLIMATE STATISTICS May 2015 This May had no significant ranking for temperature or precipitation. Avg Max Temp(F) 87.7 Normal 91.6 Avg Min Temp(F) 59.1 Normal 60.5 Avg Mean Temp(F) 73.4 Normal 76.0 Departure from Normal (F) -2.6 Highest Monthly Avg Temp (F) 80.2 in 2000 Lowest Monthly Avg Temp (F) 64.6 in 1905 Highest Temp this month (F): Lowest Temp this month (F): Record High (F): 111 on 5/29/1910 Record Low (F): 32 on 5/03/1899 104 on 31 st 50 on 10 th No temperature or precipitation records this month Tucson Number of Days of: Minimum Temp 55 o F or lower 7 Minimum Temp 60 o F or higher 15 Maximum Temp 80 o F or lower 5 Maximum Temp 90 o F or higher 13 Heating Degree Days 0 Normal 0 Cooling Degree Days 271 Normal 348 Degree base 65 o F Total May Precipitation 0.09 Normal May Precipitation 0.23 Departure from normal -0.14 Greatest 24-Hr Precipitation 0.06 on 16 th Total Precipitation Year-to-Date 3.70 Departure from Normal +0.63 Greatest May Precipitation 1.34 in 1931 Least May Precipitation 0.00 in 2011, 2002, 2000, and 47 other years Number of Days: Clear 24 Partly Cloudy 3 Cloudy 0 Average Wind Speed Highest Peak Gust 7.6 mph 38 mph from 220 o on 14 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 6.7 18 4.9 25 5.6 19 2 7.2 26 4.6 29 6.3 38 3 7 39 7.9 30 7 25 4 10.6 32 5.7 32 8.6 30 5 6.7 20 8.4 27 5.8 24 6 8 29 9.3 36 9 31 7 9.4 30 12.8 35 10.4 31 8 11.4 33 13.8 48 10.5 36 9 5.1 19 7.2 25 5.5 20 10 5.2 23 4.7 19 6.2 21 11 6.2 25 6.2 29 7.4 31 12 11.3 31 10.3 39 10.4 32 13 9.5 27 10.1 35 7.4 26 14 12.6 38 14 49 12.9 38 15 10.6 32 6.1 24 8.2 31 16 3.6 14 9.1 30 7.3 27 17 5.3 17 5.6 23 6.2 20 18 8.6 30 6.4 37 10.9 35 19 4.5 22 7.5 29 5.1 19 20 7.5 23 5.6 23 7.5 24 21 8.6 29 7.6 32 8.8 34 22 10 30 8.7 40 11.5 36 23 5.4 22 8.6 28 6 21 24 5.6 20 6.7 26 7.2 20 25 6.4 22 6.7 25 6.3 20 26 6.5 21 6.6 27 6.4 24 27 6.6 26 5.8 23 6.6 22 28 6.4 20 4.9 28 7.1 23 29 5.9 17 4.3 26 6.7 23 30 5.4 20 2 18 5.2 22 31 5.8 24 5.3 29 6.9 23 Dew Points for May: Daily Average Dew Point ( o F): Day Phx Tuc Flg 1 33 31 23 2 36 34 30 3 50 46 36 4 49 47 41 5 43 38 35 6 42 39 35 7 35 34 29 8 37 34 31 9 34 28 29 10 33 26 27 11 29 27 24 12 38 33 29 13 40 37 34 14 44 38 34 15 46 41 35 16 46 36 33 17 39 32 33 18 36 20 29 19 33 24 27 20 34 29 28 21 36 26 28 22 36 30 31 23 39 33 34 24 40 34 39 25 39 32 36 26 37 28 33 27 35 27 28 28 32 28 31 29 32 31 30 30 32 32 32 31 27 29 37 6

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May minimum temperatures were generally 0 to 6 o F cooler than average across most of the state, with a warm spot in Gila County and a much colder spot in western Pima County. Daytime temperatures were even colder than that, averaging 4 to 8 o F below normal. These lower temperatures were due to a winter circulation pattern where a series of cold low pressure systems moved down the California Coast and brought rain and even snow to the state. May precipitation was unusual as May is our driest month, but all areas of the state, except the far southeast, were well above normal this year. Drought conditions continue in the southeast counties which did not benefit from the relatively heavy spring rains. 8

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Calendar Year 2015 Calendar year minimum temperatures have been generally 0 to 6 o F warmer than average, with slightly warmer conditions in central Gila County. Daytime temperatures have been 1 to 4 o F warmer than average across the northwest half of the state, and near average in the southeast half. Western Pinal, southern Gila and most of Graham county have been 0-3 o F cooler than normal. Precipitation continued to be highly variable across the state with the wet spots (100-300% of normal) in northeastern and south central Arizona. Northwestern and central Arizona have been drier than normal. 10

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2015 Water Year The water year minimum temperatures have continued 1-4 o F warmer than average statewide, with Gila County as much as 5 o F warmer than normal. Daytime temperatures have also been 1-4 o F warmer than average across northern Arizona, with southern Arizona within 2 o F of normal, and cool pockets in western Pinal County and along the Gila-Graham County boundary. Precipitation has been well below average along much of the Mogollon Rim, northern Coconino County, Mohave County and northern Maricopa County. Southern and northeastern Arizona have received above average precipitation so far this water year. 12

May Mean Temperature Graphs Flagstaff, Phoenix, and Tucson 1895-2015: 13

May Mean Precipitation Graphs Flagstaff, Phoenix, and Tucson 1895-2015: 14

2015 Cumulative Precipitation Graphs Flagstaff, Phoenix and Tucson: Flagstaff and Tucson are near or slightly wetter than average, while Phoenix is still drier than average by almost 075. 15

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) 16