NOAA U.S. Climate Normals represent the gold standard for understanding typical climate conditions across the United States, providing statistically derived 30-year averages of weather observations from approximately 15,000 federal weather stations and thousands of citizen scientist contributors. The current dataset spans 1991-2020 and serves as the official baseline for comparing daily, monthly, and annual climate conditions to determine what constitutes "normal" weather for any location in today's climate.
The comprehensive dataset includes more than 500 types of weather and climate statistics covering temperature normals such as maximum and minimum temperatures, heating and cooling degree days, precipitation normals including rainfall, snowfall and snow depth with percentiles and frequencies, and specialized hourly normals for temperature, dew point, heat index, wind chill, wind speed, cloudiness, and atmospheric pressure. Agricultural normals provide critical data on frost-freeze date probabilities, growing degree days, temperature threshold probabilities, and growing season length calculations.
Produced in accordance with World Meteorological Organization guidelines and fulfilling a congressional mandate from the Organic Act of 1890, the Climate Normals undergo rigorous quality control processes that account for missing observations, station relocations, and instrument changes over time. The dataset incorporates data from the National Weather Service Cooperative Observer Program, Automated Surface Observing System networks, and Climate Reference Network stations to ensure comprehensive geographic coverage.
Essential for drought monitoring, agricultural planning, energy sector forecasting, construction scheduling, and climate research applications, the Climate Normals enable users to assess whether current conditions are typical or anomalous for a given location and time period. Updated every decade to incorporate climate change impacts and maintain relevance for contemporary decision-making, this authoritative resource supports evidence-based planning across agriculture, energy, transportation, emergency management, and numerous other climate-sensitive sectors.