The PRISM Group gathers weather observations from a wide range of monitoring networks, applies sophisticated quality control measures, and develops spatial datasets to reveal short- and long-term weather patterns. The resulting datasets incorporate a variety of modeling techniques and are available at multiple spatial/temporal resolutions, covering the period from 1895 to the present. Whenever possible, we offer these datasets to the public, either free of charge or for a fee (depending on dataset size/complexity and funding available for the activity).

30-Year Normals: At the end of each decade, average values for temperature and precipitation are computed over the preceding 30 years. The current set of 30-year normals covers the period 1991-2020.

Comparisons: Maps showing how observed values have been deviating from long-term conditions (also known as anomalies) - includes the new Drought Indicator tool.

This Month: Although still very preliminary, results based on daily data readings are available for the month-in-progress.

Prior 6 Months: Provisional results based on both monthly and daily data are available for the 6 most recently completed months.

Recent Years: Daily and monthly observations become stabilized after 6 months. At that point the time series datasets are posted in this section, along with annual values computed at the end of each year.

Historical Past: Values prior to 1981 are based on less extensive observations. Time series datasets computed using monthly modeling are available for the years 1895-1990.

Projects: Map images and data prepared for outside agencies but now released for public use. Includes USDA Plant Hardiness Zone Maps, data for areas outside the continental U.S., and map images for individual states.

Data Explorer: analyze and download time-series data for a single location.

FAQ: Answers to frequently asked questions