State Precipitation & Temperature Update for Arizona

Conditions through January 2013

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 100^th 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 100^th 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. The percentiles have shifted to reflect the percentile categories used in the National Drought Monitor. Current update is 2/21/2013. The data are preliminary.

Precipitation Percentiles by Watershed (through January 2013)

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Temperature Percentiles by Climate Division (through January 2013)

SHORT TERM CONDITIONS: 1-6 MONTHS

January precipitation was quite wet statewide with three very cold winter storms. Alpine had over 5” of snow and Bellemont had 11”. Eight watersheds in northern and southern Arizona had average precipitation and seven in central Arizona were wetter than average. Temperatures were much colder than normal in many counties and near average in Mohave, La Paz, Yuma, Maricopa and Pinal counties. The three month period had near average or slightly wetter than average conditions, due to the wet December and January. Only San Simon was drier than average. Temperatures were near or slightly warmer than average except Coconino, Navajo and Apache counties that were cooler than average. Six month precipitation was near average in central and western Arizona, with slightly drier than average conditions in the southeast and northeast. The southwest was slightly wetter than average. Six month temperatures were warmer than average statewide, but the warmest conditions were in the southern and southwestern counties. Only Coconino, Navajo and Apache counties had near average temperatures.

Watershed	Precipitation Percentile	Climate Division	Temperature Percentile
Virgin	58.14	CD1	40.76
Upper Colorado	58.14	CD2	11.34
Little Colorado	61.90	CD3	38.66
Verde	72.09	CD4	28.15
Bill Williams	76.74	CD5	49.16
Agua Fria	67.44	CD6	57.98
Lower Gila	74.42	CD7	30.67
Salt	74.42
Lower Colorado	75.58
Upper Gila	55.81
Santa Cruz	41.86
San Pedro	34.88
Willcox Playa	41.86
San Simon	46.51
White Water Draw	45.24

January 2013: 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	54.76	CD1	84.03
Upper Colorado	54.76	CD2	38.66
Little Colorado	45.12	CD3	59.66
Verde	65.85	CD4	55.88
Bill Williams	59.52	CD5	78.57
Agua Fria	66.67	CD6	88.24
Lower Gila	57.14	CD7	65.97
Salt	71.43
Lower Colorado	66.67
Upper Gila	59.52
Santa Cruz	42.86
San Pedro	42.50
Willcox Playa	41.46
San Simon	23.81
White Water Draw	35.37

November 2012 - January 2013 (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	30.95	CD1	83.19
Upper Colorado	30.95	CD2	52.94
Little Colorado	21.95	CD3	76.47
Verde	53.66	CD4	84.03
Bill Williams	35.71	CD5	95.80
Agua Fria	45.24	CD6	94.12
Lower Gila	59.52	CD7	83.61
Salt	50.00
Lower Colorado	71.43
Upper Gila	40.48
Santa Cruz	33.33
San Pedro	22.50
Willcox Playa	24.39
San Simon	30.95
White Water Draw	26.83

August 2012 – January 2013 (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 was the driest short-term interval with drier than average conditions in the northern and southern watersheds. The central watersheds had near average precipitation. The twelve month period was very warm, with the warmest conditions in the southwest and the northeast slightly cooler.

The 24-month period was the driest long-term interval, much drier than average in all watersheds except the lower Colorado and the lower Gila. Nine watersheds were below the 20^th percentile and five were below the 10^th. The 24-month temperatures continue to be much warmer than normal, particularly the southern counties.

Watershed	Precipitation Percentile	Climate Division	Temperature Percentile
Virgin	21.43	CD1	80.93
Upper Colorado	21.43	CD2	72.88
Little Colorado	14.29	CD3	85.59
Verde	35.71	CD4	86.44
Bill Williams	30.95	CD5	96.61
Agua Fria	33.33	CD6	94.92
Lower Gila	54.76	CD7	94.92
Salt	33.33
Lower Colorado	61.90
Upper Gila	26.19
Santa Cruz	19.05
San Pedro	19.05
Willcox Playa	14.29
San Simon	19.05
White Water Draw	4.88

February 2012 - January 2013 (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	24.39	CD1	69.23
Upper Colorado	24.39	CD2	67.09
Little Colorado	24.39	CD3	82.05
Verde	19.51	CD4	88.89
Bill Williams	24.39	CD5	88.89
Agua Fria	14.63	CD6	90.60
Lower Gila	39.02	CD7	94.87
Salt	17.07
Lower Colorado	34.15
Upper Gila	7.32
Santa Cruz	7.32
San Pedro	9.76
Willcox Playa	12.20
San Simon	7.32
White Water Draw	7.32

February 2011 – January 2013 (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 was much drier than average in all but four watersheds, the Virgin, upper Colorado, Little Colorado and lower Gila. Nine watersheds were below the 18^th percentile, and eight were at or below the 10^th percentile. Temperatures for the three year period were the coolest of the long term intervals, corresponding to the increased precipitation and winter storms. The northern counties were below the 82^nd percentile, while the warmest counties in southern Arizona were above the 86^h percentile.

The 48-month period was much drier than normal as three dry years are not balanced with only one wet year. The southeastern watersheds fared the worst, but even central Arizona was dry as the Bill Williams, Agua Fria and Verde watersheds were all below the 18^th percentile. In the south, six watersheds were below the 13^th percentile, and two of those were below the 3^rd percentile. Temperatures in the south central and southeastern counties were above the 94^th percentile, while Yuma, La Paz, and Gila counties were just above the 83^rd percentile. The northern counties were all below the 76^th percentile.

Watershed	Precipitation Percentile	Climate Division	Temperature Percentile
Virgin	35.00	CD1	67.24
Upper Colorado	35.00	CD2	78.02
Little Colorado	42.50	CD3	80.17
Verde	17.50	CD4	88.79
Bill Williams	10.00	CD5	86.21
Agua Fria	7.50	CD6	88.79
Lower Gila	35.00	CD7	95.69
Salt	22.50
Lower Colorado	30.00
Upper Gila	5.00
Santa Cruz	2.50
San Pedro	7.50
Willcox Playa	10.00
San Simon	2.50
White Water Draw	7.50

February 2010 - January 2013 (36-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	38.46	CD1	66.96
Upper Colorado	38.46	CD2	76.09
Little Colorado	17.95	CD3	80.87
Verde	12.82	CD4	83.48
Bill Williams	7.69	CD5	83.48
Agua Fria	10.26	CD6	94.78
Lower Gila	38.46	CD7	95.65
Salt	20.51
Lower Colorado	30.77
Upper Gila	12.82
Santa Cruz	2.56
San Pedro	10.26
Willcox Playa	10.26
San Simon	2.56
White Water Draw	5.13

February 2009- January 2013 (48-month): percentiles of precipitation for the 15 Arizona watersheds and percentiles of temperature for the 7 climate divisions.

February 2012 Arizona Drought Update (based on precipitation data through January 2012)

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

SUMMARY

The 3-month period had near average or slightly wetter than average conditions, due to the wet December and January. Only San Simon was drier than average. Temperatures were near or slightly warmer than average except Coconino, Navajo and Apache counties that were cooler than average.

The 6-month precipitation was near average in central and western Arizona, with slightly drier than average conditions in the southeast and northeast. The southwest was slightly wetter than average. Six month temperatures were warmer than average statewide, but the warmest conditions were in the southern and southwestern counties. Only Coconino, Navajo and Apache counties had near average temperatures.