Despite a wet winter, 2005 precipitation falls short of the 30-year average

Data from our Tucson office weather station shows below-average rainfall for 2005 — that is, 9.64 inches in contrast to the “normal” 12.17 inches. Annual rainfall amounts are compared on the basis of a 30-year average. Against this expected value, Tucson came up short about 2.5 inches, or about 21 percent. During the first half of 2005, rainfall totals were above average. A moderate monsoon season brought us about 4.5 inches of rain before the wet trend began its reversal. The remainder of 2005 suffered a near lack of precipitation that caused annual totals to dip below the 30-year average. And so the drought continues…

Will conditions improve in 2006? So far (as of early January), rainfall has been nil. Like an overdrawn bank account, our current water situation is characterized by rainfall deficits that carry over from year to year. Even if 2006 breaks all records, we’ll need many more years of surplus rain to loosen the grip of our drought. Click here to open a chart comparing 2005 rainfall at our Tucson office weather station with average rainfall (PDF file; 34KB).