Sky Harbor International Airport (SKA) is the first-order weather station in the Phoenix metropolitan area. Meteorological variables from the weather station, including precipitation, are reported by the media to the general public as the official weather results for the Phoenix metropolitan area, which measures more than 15,000 square miles. While temperature is a continuous meteorological parameter that does not vary much spatially across Phoenix, precipitation is a discrete and more variable weather phenomenon, even during winter, when mid-latitude storms bring wide swaths of precipitation to Arizona. Does the precipitation measured at Sky Harbor International Airport spatially characterize precipitation in the rest of the Phoenix area during winter? Have correlations between Sky Harbor winter precipitation and the rest of the Phoenix area changed over time? Precipitation data for the months of December to March were compiled for 28 Phoenix area weather stations for the time period 1990–2004 and for 8 stations from 1954–2004. Five definitions of precipitation, including total, frequency, intensity, duration, and true intensity were developed to define precipitation. Regression equations using Sky Harbor precipitation as the independent variable were run to determine correlations and variance explained with surrounding stations. Additional regressions were run on subsets of the 1954–2004 data to determine if correlations have changed over time. Overall, Sky Harbor explains between 71 to 99% of total seasonal precipitation and between 85 to 98% of the seasonal frequency, although these numbers are significantly reduced for daily data. Locations closer to Sky Harbor are more highly correlated for all variables than those farther away. Correlation coefficients show significant changes due to the urban heat island as well from climate teleconnections.