State Precipitation & Temperature Update for Arizona

Conditions through January 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 02/20/2008. The data are preliminary.


 

Precipitation Percentiles by Watershed (through January 2008)

 

Temperature Percentiles by Climate Division (through January 2008)


SHORT TERM CONDITIONS: 1-6 MONTHS

Like December, January was extremely wet most places in the state, above the 78th percentile. The exceptions were in the northwest and southeast, where precipitation was near average. January temperatures were near average along the lower Colorado River and in the southern climate divisions, and well below average in central and northeastern Arizona where cold winter storms brought significant snowfall to the state. The three-month period of November through January has been extremely wet across most of the state, averaging between the 63rd and 95th percentile. All three months have had strong winter storms that tapped into subtropical moisture. Although all climate divisions of the state had above-average 3-month temperatures, much of the precipitation has fallen as snow, and the snow pack remains well above average. For the second month in a row, the 3-month temperatures have dropped across the state. The 6-month period precipitation was again near- to slightly below-average in the southeast, and well above average in all other watersheds. This period reflects the tail end of the wet monsoon along with the wet winter. The dry spot in the state is the Virgin watershed, which is just below the 15th percentile. The Virgin watershed received almost no monsoon precipitation, and has only received winter precipitation from a few of the storms, particularly the December events. The colder than average winter temperatures have brought all but two climate divisions down below the 85th percentile. Last month all 7 divisions were above the 85th percentile.

Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

56.76

CD1

49.12

Upper Colorado

97.37

CD2

28.95

Little Colorado

83.78

CD3

32.89

Verde

84.21

CD4

61.40

Bill Williams

89.47

CD5

54.82

Agua Fria

84.21

CD6

53.07

Lower Gila

86.84

CD7

53.07

Salt

89.47

 

Lower Colorado

84.21

 

Upper Gila

78.95

 

Santa Cruz

57.89

 

San Pedro

47.37

 

Willcox Playa

39.47

 

San Simon

86.84

 

White Water Draw

40.54

 

JANUARY 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

68.57

CD1

75.88

Upper Colorado

91.89

CD2

62.28

Little Colorado

86.11

CD3

62.28

Verde

86.11

CD4

83.33

Bill Williams

86.49

CD5

77.19

Agua Fria

86.49

CD6

78.95

Lower Gila

91.89

CD7

71.93

Salt

94.59

 

Lower Colorado

75.68

 

Upper Gila

81.08

 

Santa Cruz

83.78

 

San Pedro

71.43

 

Willcox Playa

63.89

 

San Simon

89.19

 

White Water Draw

63.89

 

NOVEMBER 2008 - JANUARY 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

14.71

CD1

76.32

Upper Colorado

83.78

CD2

77.19

Little Colorado

72.22

CD3

80.70

Verde

80.56

CD4

90.35

Bill Williams

64.86

CD5

84.21

Agua Fria

64.86

CD6

91.23

Lower Gila

75.68

CD7

84.21

Salt

81.08

 

Lower Colorado

48.65

 

Upper Gila

62.16

 

Santa Cruz

45.95

 

San Pedro

48.57

 

Willcox Playa

47.22

 

San Simon

62.16

 

White Water Draw

47.22

 

AUGUST 2008 JANUARY 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 has improved across almost every watershed with 8 watersheds well above average, 5 near average and only 2 below average. The 12-month period became warmer for most climate divisions with all climbing above the 86th percentile.

 

The 24 month period is no longer the driest long-term period. Three watersheds in the southeast are well above average, five are now near average, four are slightly below average and three remain well below average. The driest are in northwest and west central Arizona. Temperatures for the 24-month period have dropped below the 80th percentile in the northwest, and remain above the 96th percentile in the south.


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

5.71

CD1

86.73

Upper Colorado

75.68

CD2

94.69

Little Colorado

72.97

CD3

92.04

Verde

62.16

CD4

92.92

Bill Williams

43.24

CD5

93.81

Agua Fria

51.35

CD6

98.23

Lower Gila

81.08

CD7

96.46

Salt

78.38

 

Lower Colorado

59.46

 

Upper Gila

62.16

 

Santa Cruz

37.84

 

San Pedro

40.54

 

Willcox Playa

40.54

 

San Simon

62.16

 

White Water Draw

41.67

 

FEBRUARY 2008 JANUARY 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

17.65

CD1

79.46

Upper Colorado

44.44

CD2

88.39

Little Colorado

52.78

CD3

90.18

Verde

36.11

CD4

90.18

Bill Williams

19.44

CD5

91.07

Agua Fria

25.00

CD6

92.86

Lower Gila

52.78

CD7

96.43

Salt

52.78

 

Lower Colorado

38.89

 

Upper Gila

61.11

 

Santa Cruz

33.33

 

San Pedro

50.00

 

Willcox Playa

66.67

 

San Simon

30.56

 

White Water Draw

63.89

 

FEBRUARY 2007 JANUARY 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 has become the driest period with 14 watersheds below the 50th percentile, 10 below the 37th percentile, and 5 below the 22nd percentile. The driest are the Bill Williams and Agua Fria in west central Arizona and the San Simon, Santa Cruz, and San Pedro in the south. Temperatures over the three-year period remain high with all but the northwest climate division above the 89th percentile.

 

The 48-month period continues to show above average precipitation across the western and northern watersheds, near average precipitation in the central and eastern watersheds, and below average precipitation in the southern watersheds. Both the San Simon and Santa Cruz watersheds are below the 15th percentile. Two climate divisions in southern and central Arizona are above the 95th percentile for temperature, and 4 others are between the 88th and 94th percentiles. Only the northwest climate division of Mohave County is below the 77th percentile.


Watershed

Precipitation Percentile

Climate Division

Temperature Percentile

Virgin

33.33

CD1

75.68

Upper Colorado

42.86

CD2

90.99

Little Colorado

45.71

CD3

91.89

Verde

28.57

CD4

93.69

Bill Williams

11.43

CD5

89.19

Agua Fria

17.14

CD6

93.69

Lower Gila

54.29

CD7

99.10

Salt

37.14

 

Lower Colorado

48.57

 

Upper Gila

37.14

 

Santa Cruz

14.29

 

San Pedro

22.86

 

Willcox Playa

37.14

 

San Simon

11.43

 

White Water Draw

48.57

 

FEBRUARY 2006 JANUARY 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

67.74

CD1

76.36

Upper Colorado

76.47

CD2

91.82

Little Colorado

47.06

CD3

88.18

Verde

55.88

CD4

95.45

Bill Williams

50.00

CD5

88.18

Agua Fria

52.94

CD6

93.64

Lower Gila

64.71

CD7

99.09

Salt

55.88

 

Lower Colorado

82.35

 

Upper Gila

47.06

 

Santa Cruz

8.82

 

San Pedro

32.35

 

Willcox Playa

50.00

 

San Simon

14.71

 

White Water Draw

52.94

 

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

 

February 2008 Arizona Drought Update based on precipitation data through January 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

Like December, January was extremely wet most places in the state, above the 78th percentile. The exceptions were in the northwest and southeast, where precipitation was near average. January temperatures were near average along the lower Colorado River and in the southern climate divisions, and well below average in central and northeastern Arizona where cold winter storms brought significant snowfall to the state.

 

The 3-month period of November through January has been extremely wet across most of the state, averaging between the 63rd and 95th percentile. All three months have had strong winter storms that tapped into subtropical moisture. Although all climate divisions of the state had above-average 3-month temperatures, much of the precipitation has fallen as snow, and the snow pack remains well above average. For the second month in a row, the 3-month temperatures have dropped across the state.

 

The 6-month period precipitation was again near- to slightly below-average in the southeast, and well above average in all other watersheds. This period reflects the tail end of the wet monsoon along with the wet winter. The dry spot in the state is the Virgin watershed, which is just below the 15th percentile. The Virgin watershed received almost no monsoon precipitation, and has only received winter precipitation from a few of the storms, particularly the December events. The colder than average winter temperatures have brought all but two climate divisions down below the 85th percentile. Last month all 7 divisions were above the 85th percentile.

 

The 12-month period has improved across almost every watershed with 8 watersheds well above average, 5 near average and only 2 below average. The 12-month period became warmer for most climate divisions with all climbing above the 86th percentile.

 

The 24 month period is no longer the driest long-term period. Three watersheds in the southeast are well above average, five are now near average, four are slightly below average and three remain well below average. The driest are in northwest and west central Arizona. Temperatures for the 24-month period have dropped below the 80th percentile in the northwest, and remain above the 96th percentile in the south.

 

The 36-month period has become the driest period with 14 watersheds below the 50th percentile, 10 below the 37th percentile, and 5 below the 22nd percentile. The driest are the Bill Williams and Agua Fria in west central Arizona and the San Simon, Santa Cruz, and San Pedro in the south. Temperatures over the three-year period remain high with all but the northwest climate division above the 89th percentile.

 

The 48-month period continues to show above average precipitation across the western and northern watersheds, near average precipitation in the central and eastern watersheds, and below average precipitation in the southern watersheds. Both the San Simon and Santa Cruz watersheds are below the 15th percentile. Two climate divisions in southern and central Arizona are above the 95th percentile for temperature, and 4 others are between the 88th and 94th percentiles. Only the northwest climate division of Mohave County is below the 77th percentile.