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Published January 24, 2012
Precipitation(data through 1/18/12)
Data Source(s): High Plains Regional Climate Center
Precipitation since the water year began on October 1 generally has been slightly below average in most of Arizona, with exceptionally dry spots in northern Mohave, Navajo, and Apache counties. In these regions, rain and snow have totaled between 25 and 50 percent of average (Figures 2a–b). Southern Coconino County, on the other hand, experienced between 100 and 130 percent of average precipitation, mostly the result of copious snowfall in early December. The southwest corner of the state also has been wet, with precipitation measuring between 110 and 200 percent of average. Precipitation has been patchy in New Mexico; southern areas have experienced 50–90 percent of average, while northern and central parts of the state have received more than 150 percent of average. These wet spots cover parts of McKinley, Cibola, and Guadalupe counties, and correspond to the places that also experienced colder-than-average temperatures.
During the last 30 days, conditions generally have been dry, which is more reflective of the typical La Niña pattern that was not present in the first three weeks of December (Figures 2c–d). Precipitation has been very sparse in the western half of Arizona, which received between 2 and 25 percent of average precipitation. A small area in east-central Arizona was the only region that received above-average precipitation in the state. Western and northern New Mexico have been dry, while wetter conditions have covered most of the southeast corner, where rain and snow have totaled between 150 and 800 percent of average. The wet weather in this region is fortuitous, because it is the area experiencing the most severe drought.
The water year begins on October 1 and ends on September 30 of the following year. As of October 1, 2011, we are in the 2012 water year. The water year is a more hydrologically sound measure of climate and hydrological activity than is the standard calendar year.
Average refers to the arithmetic mean of annual data from 1971–2000. Percent of average precipitation is calculated by taking the ratio of current to average precipitation and multiplying by 100.
The continuous color maps (Figures 2a, 2c) are derived by taking measurements at individual meteorological stations and mathematically interpolating (estimating) values between known data points. Interpolation procedures can cause aberrant values in data-sparse regions.
The dots in Figures 2b and 2d show data values for individual meteorological stations.
For these and other precipitation maps, visit:
For National Climatic Data Center monthly precipitation and drought reports for Arizona, New Mexico, and the Southwest region, visit :
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Dan Ferguson, CLIMAS Program Director
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, CLIMAS Associate Staff Scientist
- Gigi Owen, CLIMAS Assistant Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Swetish, CLIMAS Publications Assistant
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
The CLIMAS Web site contains official and non-official forecasts, as well as other information. While we make every effort to verify this information, please understand that we do not warrant the accuracy of any of these materials.... Read full disclaimer