State Precipitation & Temperature Update for Arizona

Conditions through March 2008

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 04/24/2008. The data are preliminary.


 

Precipitation Percentiles by Watershed (through March 2008)

 

Temperature Percentiles by Climate Division (through March 2008)


SHORT TERM CONDITIONS: 1-6 MONTHS

March was extremely dry across the entire state. Precipitation was below the 15th percentile for all watersheds except the upper Colorado, Virgin and lower Gila. Only one significant winter storm moved through the state during March. Temperatures were only slightly above average for the month across most of the state, except in the southwest corner which had temperatures above the 85th percentile. The three-month winter period of January through March was wetter than average across the northwest 2/3 of the state, and drier than average in the southeastern third of the state. Virtually all of that precipitation fell in January and February. The three month period was near average in central and northwestern Arizona, warmer than average in southern Arizona, and colder than average in northeast Arizona. The cooler temperatures in the higher elevations helped to maintain the snowpack this year. The 6-month period precipitation, from October through March, was near- to slightly above-average in most watersheds. The northwest and southeast corners of the state saw few winter storms and received below average precipitation this winter. The northern half of the state had winter temperatures between the 61st and 71st percentile, while the southern half of the state had temperatures between the 78th and 90th percentiles. Overall, the temperature conditions matched the Climate Prediction Centers forecast of a warmer than average winter.

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

18.42

CD1

72.37

Upper Colorado

26.32

CD2

65.79

Little Colorado

10.53

CD3

74.56

Verde

10.53

CD4

82.89

Bill Williams

13.16

CD5

85.09

Agua Fria

13.16

CD6

82.89

Lower Gila

15.79

CD7

64.91

Salt

5.26

 

Lower Colorado

7.89

 

Upper Gila

7.89

 

Santa Cruz

13.16

 

San Pedro

10.53

 

Willcox Playa

10.53

 

San Simon

13.16

 

White Water Draw

5.26

 

MARCH 2008: 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

35.14

CD1

55.26

Upper Colorado

76.32

CD2

34.65

Little Colorado

62.16

CD3

44.30

Verde

60.53

CD4

64.04

Bill Williams

60.53

CD5

61.84

Agua Fria

57.89

CD6

57.89

Lower Gila

60.53

CD7

61.40

Salt

65.79

 

Lower Colorado

50.00

 

Upper Gila

39.47

 

Santa Cruz

34.21

 

San Pedro

23.68

 

Willcox Playa

18.92

 

San Simon

47.37

 

White Water Draw

18.92

 

JANUARY 2008 - MARCH 2008 (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

34.29

CD1

62.28

Upper Colorado

70.27

CD2

61.40

Little Colorado

55.56

CD3

67.54

Verde

58.33

CD4

89.47

Bill Williams

48.65

CD5

70.18

Agua Fria

56.76

CD6

78.95

Lower Gila

67.57

CD7

82.46

Salt

64.86

 

Lower Colorado

51.35

 

Upper Gila

45.95

 

Santa Cruz

51.35

 

San Pedro

40.00

 

Willcox Playa

30.56

 

San Simon

62.16

 

White Water Draw

33.33

 

OCTOBER 2008 MARCH 2008 (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 had near- to above-average precipitation in 11 watersheds, and below-average precipitation in the Virgin, Santa Cruz, San Pedro and Willcox watersheds. Temperatures were above the 75th percentile for all climate divisions, with the highest temperatures in the south.

 

The 24-month period was much drier than it was last month, with no watersheds above the 59th percentile. Three watersheds are still at or below the 25th percentile, nine are between the 40th and 59th percentiles, while last month six watersheds were above the 60th percentile. Temperatures for the 24-month period warmed above the 86th percentile everywhere but the northwest, where they dropped slightly to the 78th percentile.


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

8.57

CD1

76.99

Upper Colorado

72.97

CD2

82.74

Little Colorado

64.86

CD3

90.27

Verde

54.05

CD4

93.81

Bill Williams

45.95

CD5

88.50

Agua Fria

45.95

CD6

95.58

Lower Gila

75.68

CD7

96.46

Salt

70.27

 

Lower Colorado

59.46

 

Upper Gila

51.35

 

Santa Cruz

35.14

 

San Pedro

35.14

 

Willcox Playa

36.11

 

San Simon

56.76

 

White Water Draw

41.67

 

APRIL 2008 MARCH 2008 (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

8.82

CD1

77.68

Upper Colorado

44.44

CD2

90.18

Little Colorado

55.56

CD3

92.86

Verde

30.56

CD4

91.96

Bill Williams

13.89

CD5

92.86

Agua Fria

25.00

CD6

93.75

Lower Gila

52.78

CD7

97.32

Salt

47.22

 

Lower Colorado

41.67

 

Upper Gila

47.22

 

Santa Cruz

33.33

 

San Pedro

44.44

 

Willcox Playa

58.33

 

San Simon

38.89

 

White Water Draw

58.33

 

APRIL 2007 MARCH 2008 (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 period continues to be the driest period with all watersheds below the 35th percentile. Nine watersheds are below the 22nd percentile with seven below the 15th percentile. The Northwest climate division is above the 75th percentile and the other six climate divisions are above the 88th percentile. Division 7 had its warmest 4-year period since 1895.

 

The 48-month period continues to have above-average precipitation in the western watersheds, below-average precipitation in the southeastern watersheds, and near- average precipitation in the central watersheds. Santa Cruz and San Pedro continue to be the driest long-term watersheds, and this month the lower Gila dropped below the 40th percentile. The upper and lower Colorado are the wettest watersheds, at the 76th percentile. Only the northwest climate division of Mohave County remains below the 86th percentile for temperature, though 48-month temperatures have dropped slightly since last month.


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

21.21

CD1

75.23

Upper Colorado

31.43

CD2

88.29

Little Colorado

25.71

CD3

90.99

Verde

14.29

CD4

94.59

Bill Williams

5.71

CD5

88.29

Agua Fria

5.71

CD6

97.30

Lower Gila

28.57

CD7

100.00

Salt

14.29

 

Lower Colorado

25.71

 

Upper Gila

14.29

 

Santa Cruz

8.57

 

San Pedro

20.00

 

Willcox Playa

31.43

 

San Simon

8.57

 

White Water Draw

34.29

 

APRIL 2006 MARCH 2008 (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

61.29

CD1

75.45

Upper Colorado

76.47

CD2

88.18

Little Colorado

44.12

CD3

87.73

Verde

58.82

CD4

95.45

Bill Williams

50.00

CD5

86.36

Agua Fria

47.06

CD6

91.82

Lower Gila

61.76

CD7

99.09

Salt

47.06

 

Lower Colorado

76.47

 

Upper Gila

35.29

 

Santa Cruz

8.82

 

San Pedro

14.71

 

Willcox Playa

41.18

 

San Simon

29.41

 

White Water Draw

47.06

 

APRIL 2005 MARCH 2008 (48-month): percentiles of temperature, and precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

 

April 2008 Arizona Drought Update based on precipitation data through March 2008)

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

 

SUMMARY

March was extremely dry across the entire state. Precipitation was below the 15th percentile for all watersheds except the upper Colorado, Virgin and lower Gila. Only one significant winter storm moved through the state during March. Temperatures were only slightly above average for the month across most of the state, except in the southwest corner which had temperatures above the 85th percentile.

 

The 3-month winter period of January through March was wetter than average across the northwest 2/3 of the state, and drier than average in the southeastern third of the state. Virtually all of that precipitation fell in January and February. The three month period was near average in central and northwestern Arizona, warmer than average in southern Arizona, and colder than average in northeast Arizona. The cooler temperatures in the higher elevations helped to maintain the snowpack this year.

 

The 6-month period precipitation, from October through March, was near- to slightly above-average in most watersheds. The northwest and southeast corners of the state saw few winter storms and received below average precipitation this winter. The northern half of the state had winter temperatures between the 61st and 71st percentile, while the southern half of the state had temperatures between the 78th and 90th percentiles. Overall, the temperature conditions matched the Climate Prediction Centers forecast of a warmer than average winter.

 

The 12-month period had near- to above-average precipitation in 11 watersheds, and below-average precipitation in the Virgin, Santa Cruz, San Pedro and Willcox watersheds. Temperatures were above the 75th percentile for all climate divisions, with the highest temperatures in the south.

 

The 24-month period was much drier than it was last month, with no watersheds above the 59th percentile. Three watersheds are still at or below the 25th percentile, nine are between the 40th and 59th percentiles, while last month six watersheds were above the 60th percentile. Temperatures for the 24-month period warmed above the 86th percentile everywhere but the northwest, where they dropped slightly to the 78th percentile.

 

The 36-month period continues to be the driest period with all watersheds below the 35th percentile. Nine watersheds are below the 22nd percentile with seven below the 15th percentile. The Northwest climate division is above the 75th percentile and the other six climate divisions are above the 88th percentile. Division 7 had its warmest 4-year period since 1895.

 

The 48-month period continues to have above-average precipitation in the western watersheds, below-average precipitation in the southeastern watersheds, and near- average precipitation in the central watersheds. Santa Cruz and San Pedro continue to be the driest long-term watersheds, and this month the lower Gila dropped below the 40th percentile. The upper and lower Colorado are the wettest watersheds, at the 76th percentile. Only the northwest climate division of Mohave County remains below the 86th percentile for temperature, though 48-month temperatures have dropped slightly since last month.