Yavapai County Climate Jeff Schalau Agent, Agriculture & Natural Resources University of Arizona Cooperative Extension Yavapai County

Arizona’s Climate Bimodal Precipitation Pattern Wide Diurnal Temperature Fluctuations Elevation Differences Cause Variability Highly Variable Summer Precipitation Periodic Drought Monsoon Most Dependable in Southeastern Portion of the State

Freeze Probabilities - Prescott Spring Freeze Probabilities (32.5 degrees F) Earliest 90% 80% 70% 60% 50% 40% 30% 20% 10% Latest 4/14 4/26 5/3 5/8 5/13 5/18 5/21 5/26 5/31 6/2 6/17 Fall Freeze Probabilities (32.5 degrees F) Earliest 10% 20% 30% 40% 50% 60% 70% 80% 90% Latest 8/23 9/20 9/25 10/1 10/5 10/11 10/14 10/16 10/21 10/27 11/5 Average Growing Season = 140 days

Freeze Probabilities - Cottonwood Spring Freeze Probabilities (32.5 degrees F) Earliest 90% 80% 70% 60% 50% 40% 30% 20% 10% Latest 3/11 3/24 3/26 4/3 4/9 4/15 4/20 4/25 4/29 5/5 5/8 Fall Freeze Probabilities (32.5 degrees F) Earliest 10% 20% 30% 40% 50% 60% 70% 80% 90% Latest 10/18 10/24 10/25 10/29 11/4 11/7 11/10 11/12 11/14 11/18 11/25 Average Growing Season = 194 days

El Nino and La Nina Related to temperature and current in the equatorial Pacific Ocean El Nino increases the probability of winter precipitation for Arizona La Nina almost always forecasts low winter precipitation for Arizona