State Precipitation & Temperature Update for Arizona

Conditions through December 2006

Precipitation is monitored for the state of Arizona across the 15 major watersheds (see map left). From the stations within each watershed, mean values of precipitation for the watershed as a whole are computed. These mean values are ranked against the monthly mean values for the period of 1971-present. The rankings are then divided by the number of years of data and multiplied by 100% to create percentiles.

 

Here, precipitation percentile values for the most recent month, along with previous 3-, 6-, 12-, 24-, 36-, and 48-month total are shown for each watershed. Low percentile values (brown shading) indicate dry conditions while high values (green shading) indicate wet conditions. For example, a precipitation total that falls at the 100th percentile means that it is the highest precipitation total for the 1971-present period.

 

Temperature is monitored for the state of Arizona across seven climate divisions (see map left). From the stations within each climate division, mean values of temperature for the climate division as a whole are computed. These mean values are ranked against the monthly mean values for the period of 1895-present. The rankings are then divided by the number of years of data and multiplied by 100% to create percentiles.

 

Here, temperature percentile values for the most recent month, along with previous 3-, 6-, 12-, 24-, 36-, and 48-month averages are shown for each climate division. Low percentile values (blue shading) indicate cool conditions while high values (orange/red shading) indicate hot conditions. For example, a temperature that falls at the 100th percentile means that it is the highest average temperature for the 1895-present period.

 

The maps of the seven periods for precipitation and temperature are shown below, with tables of the percentile values and descriptive text following the maps. Current update is 1/24/2007. The data are preliminary, and there are some missing precipitation data in the San Pedro watershed.


 

Precipitation Percentiles by Watershed (through December 2006)

 

Temperature Percentiles by Climate Division (through December 2006)


SHORT TERM CONDITIONS: 1-6 MONTHS

December precipitation was near or below average everywhere in the state except in the Upper Colorado, Willcox and White Water Draw watersheds. Precipitation in the Bill Williams and San Simon watersheds was at or below the 25th percentile. Temperatures were near average in the northwest and southeast, slightly above average on the Colorado Plateau, and below average in Maricopa and Pinal counties and the Lower Colorado River. The 3-month period of October through December was also much drier than average, with the driest watersheds across the southern half of the state. Temperatures over the 3-month period were slightly above average for most of the state, and above the 75th percentile in Maricopa and Pinal counties. The 6-month period, July through December, which includes the wet monsoon, is still above average for the eastern half of the state, and near or below average for the western half of the state. The extreme monsoon moisture in the San Pedro and Willcox basins pushed them up above the 79th percentile for this period. Temperatures were above average everywhere in the state for the past six months and above the 75th percentile for the far western and central climate divisions.

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

77.78

CD1

55.80

Upper Colorado

52.78

CD2

63.84

Little Colorado

38.89

CD3

56.25

Verde

37.14

CD4

46.43

Bill Williams

19.44

CD5

20.09

Agua Fria

27.78

CD6

26.34

Lower Gila

36.11

CD7

45.09

Salt

27.78

 

Lower Colorado

33.33

 

Upper Gila

36.11

 

Santa Cruz

36.11

 

San Pedro

38.24

 

Willcox Playa

43.06

 

San Simon

25.00

 

White Water Draw

41.67

 

DECEMBER 2006: percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

51.43

CD1

73.66

Upper Colorado

66.67

CD2

73.21

Little Colorado

44.44

CD3

70.09

Verde

34.29

CD4

67.86

Bill Williams

30.56

CD5

68.30

Agua Fria

16.67

CD6

79.02

Lower Gila

13.89

CD7

70.09

Salt

30.56

 

Lower Colorado

38.89

 

Upper Gila

22.22

 

Santa Cruz

11.11

 

San Pedro

20.59

 

Willcox Playa

20.00

 

San Simon

5.56

 

White Water Draw

27.78

 

OCTOBER 2006 - DECEMBER 2006 (3-month): percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

32.35

CD1

76.79

Upper Colorado

55.56

CD2

60.71

Little Colorado

58.33

CD3

69.20

Verde

48.57

CD4

54.02

Bill Williams

22.22

CD5

83.04

Agua Fria

38.89

CD6

78.13

Lower Gila

30.56

CD7

54.46

Salt

44.44

 

Lower Colorado

55.56

 

Upper Gila

58.33

 

Santa Cruz

61.11

 

San Pedro

79.41

 

Willcox Playa

85.71

 

San Simon

27.78

 

White Water Draw

65.71

 

JULY 2006 DECEMBER 2006 (6-month): percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

 

INTERMEDIATE TERM CONDITIONS: 12-24 MONTHS

Precipitation in the 12-month period is well below average across most of the state, except for the southeast watersheds which benefited from an extremely wet monsoon. The southeast and south central division is still the hottest, above the 96th percentile, and the rest of the state remains above the 77th percentile.

The two-year period shows only the Upper and Lower Colorado and Virgin River watersheds still above the 50th percentile. The Santa Cruz and San Simon watersheds in the south central part of the state are extremely dry, below the 20th percentile. For temperature, the southeast climate division remained above the 99th percentile and most of the state was above the 87th percentile, while the northwest was the cool spot, in the 75th percentile.


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

47.06

CD1

77.48

Upper Colorado

19.44

CD2

85.14

Little Colorado

25.00

CD3

88.29

Verde

11.11

CD4

90.99

Bill Williams

5.56

CD5

91.89

Agua Fria

11.11

CD6

93.69

Lower Gila

13.89

CD7

98.20

Salt

11.11

 

Lower Colorado

19.44

 

Upper Gila

41.67

 

Santa Cruz

30.56

 

San Pedro

47.22

 

Willcox Playa

55.56

 

San Simon

5.56

 

White Water Draw

47.22

 

JANUARY 2006 DECEMBER 2006 (12-month): percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

81.82

CD1

75.45

Upper Colorado

54.29

CD2

91.82

Little Colorado

34.29

CD3

88.18

Verde

40.00

CD4

91.82

Bill Williams

25.71

CD5

87.27

Agua Fria

34.29

CD6

93.64

Lower Gila

42.86

CD7

99.09

Salt

34.29

 

Lower Colorado

60.00

 

Upper Gila

42.86

 

Santa Cruz

17.14

 

San Pedro

37.14

 

Willcox Playa

42.86

 

San Simon

11.43

 

White Water Draw

45.71

 

JANUARY 2005 DECEMBER 2006 (24-month): percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

LONG TERM CONDITIONS: 36-48 MONTHS

The 36-month precipitation is well above average in the northern and western watersheds and below average in the south central watersheds and the Colorado Plateau. The rest of the state is near or above average. The Santa Cruz and San Simon watersheds continue to be the driest. Gila county moved up above the 95th percentile for temperature, and the coolest area is still the northwest in the 76th percentile.

 

The 48-month precipitation is still split across the state with the eastern half drier than average and the western half wetter than average. The central watersheds remain near normal. Temperatures are above the 97th percentile for most of the southern half of the state. The Lower Colorado River divisions are slightly cooler than the central or eastern divisions, but all divisions remain above the 77th percentile.

 

 


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

90.62

CD1

76.15

Upper Colorado

73.53

CD2

90.83

Little Colorado

38.24

CD3

88.99

Verde

55.88

CD4

95.41

Bill Williams

55.88

CD5

88.07

Agua Fria

47.06

CD6

92.66

Lower Gila

58.82

CD7

100.00

Salt

44.12

 

Lower Colorado

76.47

 

Upper Gila

44.12

 

Santa Cruz

8.82

 

San Pedro

44.12

 

Willcox Playa

47.06

 

San Simon

14.71

 

White Water Draw

50.00

 

JANUARY 2004 DECEMBER 2006 (36-month): percentiles of temperature, and precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

-99.99

CD1

77.78

Upper Colorado

69.70

CD2

92.59

Little Colorado

18.18

CD3

94.44

Verde

54.55

CD4

98.15

Bill Williams

51.52

CD5

91.20

Agua Fria

45.45

CD6

97.22

Lower Gila

60.61

CD7

100.00

Salt

36.36

 

Lower Colorado

69.70

 

Upper Gila

21.21

 

Santa Cruz

15.15

 

San Pedro

21.21

 

Willcox Playa

18.18

 

San Simon

15.15

 

White Water Draw

30.30

 

JANUARY 2003 DECEMBER 2006 (48-month): percentiles of temperature, and precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

January 2007 Arizona Drought Update based on Precipitation (data through December 2006)

The following summary describes the heat and dryness across the state for the 1-, 3-, 6-, 12-, 24-, 36-, and 48-month periods.

 

SUMMARY

December was not as dry as November, but most watersheds had below average precipitation, except the Upper Colorado, Willcox and White Water Draw watersheds. Most of the winter storms tracks so far have been well to the north of the state. Temperatures were near average in the northwest and southeast, slightly above average on the Colorado Plateau, and below average in Maricopa and Pinal counties and the Lower Colorado River.

 

Three-month period October through December was also much drier than average, with the driest watersheds across the southern half of the state. Temperatures were slightly above average for most of the state, and above the 75th percentile in Maricopa and Pinal counties.

 

Six-month period July through December, which includes the wet monsoon, is still above average for the eastern half of the state, and near or below average for the western half of the state. The extreme monsoon moisture in the San Pedro and Willcox basins pushed them up above the 79th percentile for this period. Temperatures were above average everywhere in the state for the past six months and above the 75th percentile for the far western and central climate divisions.

 

Twelve-month period precipitation is well below average across most of the state, except for the southeast watersheds which benefited from an extremely wet monsoon. The southeast-south central division is still the hottest, above the 96th percentile, and the rest of the state remains above the 77th percentile.

 

Two-year period - shows only the Upper and Lower Colorado and Virgin River watersheds still above the 50th percentile. The Santa Cruz and San Simon watersheds in the south central part of the state are extremely dry, below the 20th percentile. For temperature, the southeast climate division remained above the 99th percentile and most of the state was above the 87th percentile, while the northwest was the cool spot, in the 75th percentile.

 

Three-year period - precipitation is well above average in the northern and western watersheds and below average in the south central watersheds and the Colorado Plateau. The rest of the state is near or above average. The Santa Cruz and San Simon watersheds continue to be the driest. Gila county moved up above the 95th percentile for temperature, and the coolest area is still the northwest in the 76th percentile.

 

Four-year period - precipitation is still split across the state with the eastern half drier than average and the western half wetter than average. The central watersheds remain near normal. Temperatures are above the 97th percentile for most of the southern half of the state. The Lower Colorado River divisions are slightly cooler than the central or eastern divisions, but all divisions remain above the 77th percentile.