State Precipitation & Temperature Update for Arizona

Conditions through November 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 12/28/2006.  Note the San Pedro has preliminary precipitation data only.


 

Precipitation Percentiles by Watershed (through November 2006)

 

Temperature Percentiles by Climate Division (through November 2006)


SHORT TERM CONDITIONS: 1-6 MONTHS

November precipitation was well below average everywhere in the state, not even reaching the 15th percentile.  Temperatures were above average everywhere in the state, increasing the water demand by vegetation.  The 3-month period gained a very dry November and dropped a very wet August.  The Salt, Lower Gila and Bill Williams watersheds had near average precipitation for the 3-month period, while the Upper and Lower Colorado and the southeast corner had slightly above average precipitation.  Precipitation in the Little Colorado, Verde, Agua Fria, Santa Cruz and San Simon watersheds was slightly below average. Temperatures over the 3-month period were near average for most of the state, and well above average in the southwest and south central divisions.  The 6-month period, June through November, which includes the wet monsoon, is still above average for the eastern half of the state, and near or slightly 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 88th percentile.  Temperatures were above the 78th percentile everywhere in the state for the summer and fall and above the 96th percentile for the southwest and west central divisions.

 

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

8.57

CD1

83.93

Upper Colorado

13.89

CD2

87.05

Little Colorado

13.89

CD3

91.07

Verde

11.11

CD4

91.96

Bill Williams

11.11

CD5

97.32

Agua Fria

8.33

CD6

98.21

Lower Gila

5.56

CD7

88.84

Salt

11.11

 

Lower Colorado

9.72

 

Upper Gila

5.56

 

Santa Cruz

11.11

 

San Pedro

5.56

 

Willcox Playa

8.57

 

San Simon

11.11

 

White Water Draw

11.11

 

NOVEMBER 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

41.18

CD1

67.86

Upper Colorado

63.89

CD2

44.64

Little Colorado

36.11

CD3

50.89

Verde

36.11

CD4

44.20

Bill Williams

44.44

CD5

88.39

Agua Fria

27.78

CD6

91.96

Lower Gila

33.33

CD7

54.02

Salt

41.67

 

Lower Colorado

63.89

 

Upper Gila

41.67

 

Santa Cruz

25.00

 

San Pedro

63.89

 

Willcox Playa

60.00

 

San Simon

30.56

 

White Water Draw

61.11

 

SEPTEMBER 2006 - NOVEMBER 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

29.41

CD1

80.36

Upper Colorado

55.56

CD2

78.57

Little Colorado

61.11

CD3

85.27

Verde

63.89

CD4

81.70

Bill Williams

30.56

CD5

97.32

Agua Fria

50.00

CD6

96.43

Lower Gila

38.89

CD7

87.95

Salt

61.11

 

Lower Colorado

61.11

 

Upper Gila

75.00

 

Santa Cruz

72.22

 

San Pedro

94.44

 

Willcox Playa

88.57

 

San Simon

52.78

 

White Water Draw

71.43

 

JUNE 2005 – NOVEMBER 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

The 12-month period shows little change from last month’s update, with only three watersheds in the southeast corner near average for precipitation.  The Virgin, Upper Gila and Santa Cruz are slightly below average and the other nine watersheds are all below the 23rd percentile.  The warm November pushed the 12-month temperature percentiles even higher.  The southeast and south central divisions are still the hottest, above the 96th percentile, and the rest of the state is above the 77th percentile.

 

The two-year period shows the Colorado and Virgin River watersheds still above the 75th percentile, while the most of the state has dropped to near average, except the Santa Cruz and San Simon watersheds, which are still below the 21st percentile.  The 24-month temperatures were well above the 85th percentile everywhere except the Northwest division, which dropped down to the 72nd percentile.  The southeast climate division had its warmest 24-month period since 1895, and climate division six, which includes Maricopa County, moved up above the 96th percentile.

 


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

39.39

CD1

77.48

Upper Colorado

20.00

CD2

87.84

Little Colorado

22.86

CD3

87.84

Verde

11.43

CD4

90.99

Bill Williams

5.71

CD5

92.79

Agua Fria

11.43

CD6

96.40

Lower Gila

14.29

CD7

98.20

Salt

14.29

 

Lower Colorado

20.00

 

Upper Gila

37.14

 

Santa Cruz

25.71

 

San Pedro

48.57

 

Willcox Playa

57.14

 

San Simon

11.43

 

White Water Draw

51.43

 

DECEMBER 2005 – NOVEMBER 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

87.50

CD1

71.82

Upper Colorado

64.71

CD2

92.73

Little Colorado

44.12

CD3

90.00

Verde

47.06

CD4

92.73

Bill Williams

38.24

CD5

89.09

Agua Fria

44.12

CD6

96.36

Lower Gila

52.94

CD7

100.00

Salt

44.12

 

Lower Colorado

64.71

 

Upper Gila

50.00

 

Santa Cruz

20.59

 

San Pedro

41.18

 

Willcox Playa

47.06

 

San Simon

14.71

 

White Water Draw

55.88

 

DECEMBER 2004 – NOVEMBER 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 rankings remain the same since the November update, except the Upper Gila watershed has dropped below the 40th percentile.  The western half of the state remains near or above-average, while the eastern half of the state is near or below-average, The Santa Cruz and San Simon watersheds continue to be the driest.  Climate division six moved up above the 96th percentile for temperature with the warm November.  The entire state remains above the 75th percentile.

 

The 48-month precipitation pattern has degraded with the eastern half of the state well below average for precipitation, the central watersheds near normal and the Colorado River watersheds slightly above average.  Temperatures are above the 96th percentile in the southeast and south central climate divisions, above the 91st percentile on the plateau and the southwest, and above the 77th percentile in the Northwest. 

 

 


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

93.55

CD1

75.23

Upper Colorado

69.70

CD2

90.83

Little Colorado

30.30

CD3

89.91

Verde

54.55

CD4

95.41

Bill Williams

51.52

CD5

88.07

Agua Fria

45.45

CD6

96.33

Lower Gila

60.61

CD7

99.08

Salt

45.45

 

Lower Colorado

81.82

 

Upper Gila

39.39

 

Santa Cruz

9.09

 

San Pedro

33.33

 

Willcox Playa

45.45

 

San Simon

18.18

 

White Water Draw

48.48

 

DECEMBER 2003 – NOVEMBER 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

68.75

CD2

91.20

Little Colorado

21.88

CD3

94.44

Verde

50.00

CD4

97.22

Bill Williams

56.25

CD5

93.52

Agua Fria

40.62

CD6

96.30

Lower Gila

56.25

CD7

100.00

Salt

37.50

 

Lower Colorado

75.00

 

Upper Gila

25.00

 

Santa Cruz

15.62

 

San Pedro

25.00

 

Willcox Playa

18.75

 

San Simon

21.88

 

White Water Draw

25.00

 

DECEMBER 2002 – NOVEMBER 2006 (48-month): percentiles of temperature, and precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

December 2006 Arizona Drought Update based on Precipitation (data through November 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

While October was cool and wet across most of the state, November brought warm dry weather to all of Arizona.  Precipitation was below the 15th percentile, while temperatures were above the 83rd percentile.  The warmest areas were the southwest and west central divisions.  The dry start to the winter is not, however, contradictory to the predictions of a relatively wet winter due to El Nińo.  El Nińo generally brings wetter weather beginning in January, and the El Nińo pattern appears to be strengthening.

 

Three-month period – The 3-month period gained a very dry November and dropped a very wet August.  Only the Upper and Lower Colorado and the southeast corner had above average precipitation.  Temperatures over the 3-month period were near average for most of the state, and well above average in the southwest and south central divisions.

 

Six-month period – includes the wet monsoon, so precipitation is still above average for the eastern half of the state, and near or slightly 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 88th percentile.  Temperatures were above the 78th percentile everywhere in the state for the summer and fall and above the 96th percentile for the southwest and west central divisions.

 

Twelve-month period - shows little change from last month’s update, with only three watersheds in the southeast corner near average for precipitation.  The Virgin, Upper Gila and Santa Cruz are slightly below average and the other nine watersheds are all below the 23rd percentile.  The warm November pushed the 12-month temperature percentiles even higher.  The southeast and south central divisions are still the hottest, above the 96th percentile, and the rest of the state is above the 77th percentile.

 

Two-year period - shows the Colorado and Virgin River watersheds still above the 75th percentile, while the most of the state has dropped to near average, except the Santa Cruz and San Simon watersheds, which are still below the 21st percentile.  The 24-month temperatures were well above the 85th percentile everywhere except the Colorado Plateau, which dropped down to the 72nd percentile.  The southeast climate division had its warmest 24-month period since 1895, and climate division six, which includes Maricopa County, moved above the 96th percentile.

 

Three-year period - rankings remain the same since the November update, except the Upper Gila watershed has dropped below the 40th percentile.  The western half of the state remains near or above-average, while the eastern half of the state is near or below-average, The Santa Cruz and San Simon watersheds continue to be the driest.  Climate division six moved up above the 96th percentile for temperature with the warm November.  The entire state remains above the 75th percentile.

 

Four-year period - precipitation pattern has degraded with the eastern half of the state well below average for precipitation, the central watersheds near average and the Colorado River watersheds slightly above average.  Temperatures are still extremely warm across the entire state.