U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991-2020)

browse graphicAccumulated Precipitation Normal from January 1 to May 1
The Monthly Climate Normals for 1991 to 2020 are 30-year averages of meteorological parameters that provide users the information needed to understand typical climate conditions for thousands of locations across the United States, as well as U.S. Territories and Commonwealths, and the Compact of Free Association nations. The stations used include those from the NWS Cooperative Observer Program (COOP) Network as well as some additional stations that have a Weather Bureau Army-Navy (WBAN) station identification number, including stations from the U.S. Climate Reference Network (USCRN) and other automated observation stations. In addition, precipitation normals for stations from the U.S. Snow Telemetry (SNOTEL) Network and the citizen-science Community Collaborative Rain, Hail and Snow (CoCoRaHS) Network are also available. The Monthly Climate Normals dataset includes various derived products such as air temperature normals (including maximum and minimum temperature normals, heating and cooling degree day normals, and others), precipitation normals (including precipitation and snowfall totals, and percentiles, frequencies and other statistics of precipitation, snowfall, and snow depth), and agricultural normals (growing degree days (GDDs)). All data utilized in the computation of the 1991-2020 Climate Normals were taken from the Global Historical Climatology Network-Daily and -Monthly datasets. Temperatures were homogenized, adjusted for time-of-observation, and made serially complete where possible based on information from nearby stations. Precipitation totals were also made serially complete where possible based using nearby stations. The source datasets (including intermediate datasets used in the computation of products) are also archived at NOAA NCEI. A comparatively small number of station normals sets (~50) have been added as Version 1.0.1 to correct quality issues or because additional historical data during the 1991-2020 period has been ingested.
  • Cite as: Palecki, Michael; Durre, Imke; Applequist, Scott; Arguez, Anothony; Lawrimore, Jay. 2021: U.S. Climate Normals 2020: U.S. Hourly Climate Normals (1991-2020). [indicate subset used]. NOAA National Centers for Environmental Information. https/doi.org/{{DOI}}. Accessed [date].
  • NCE DSI: 2049_01
  • gov.noaa.ncdc:C01620
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Distribution Formats
  • CSV (Version: 1.0)
Ordering InstructionsContact NCEI for other distribution options and instructions.
DistributorNOAA National Centers for Environmental Information
ncei.info@noaa.gov
Dataset Principal Investigator Michael Palecki
Project Manager for Normals
National Centers for Environmental Information/NOAA
8282714340
michael.palecki@noaa.gov
Time Period1991-01 to 2020-12 (time interval: 1-month)
Spatial Reference Systemurn:ogc:def:crs:EPSG::4269
Spatial Bounding Box Coordinates
N: 72.0
S: -15.0
E: -64.0
W: 134.0
Spatial Coverage Map
General Documentation
Associated Resources
Publication Dates
  • publication: 2023-05-15
Edition1.0.1
Data Presentation Form Digital document - digital representation of a primarily textual item (can contain illustrations also)
Dataset Progress StatusComplete - production of the data has been completed
Data Update Frequency As needed
PurposeNOAA NCEI and NOAA NWS will be primary users of this dataset. Other users include many federal, state, and local government agencies; corporations and individuals in all U.S. Economic Sectors, and the general public. The archived data will be be used to compare local climates across the United States. It will also be used to place current observations in context by allowing the calculation of anomalies (differences from normals) from a consistent reference period of record.
Use Limitations
  • These normals are calculated at weather stations and are limited in their applicability at locations in between stations as distance from the station increases horizontally and vertically.
Dataset Citation
  • Cite as: Palecki, Michael; Durre, Imke; Applequist, Scott; Arguez, Anothony; Lawrimore, Jay. 2021: U.S. Climate Normals 2020: U.S. Hourly Climate Normals (1991-2020). [indicate subset used]. NOAA National Centers for Environmental Information. https/doi.org/{{DOI}}. Accessed [date].
Cited Authors
  • Palecki, Michael
    National Centers for Environmental Information/NOAA
  • Durre, Imke
    National Centers for Environmental Information/NOAA
  • Applequist, Scott
    National Centers for Environmental Information/NOAA
  • Arguez, Anthony
    National Centers for Environmental Information/NOAA
  • Lawrimore, Jay
    National Centers for Environmental Information/NOAA
Principal Investigators
  • Palecki, Michael
    National Centers for Environmental Information/NOAA
Processors
  • Durre, Imke
    National Centers for Environmental Information/NOAA
  • Applequist, Scott
    National Centers for Environmental Information/NOAA
  • Arguez, Anthony
    National Centers for Environmental Information/NOAA
Sponsors
  • Durre, Imke
    National Centers for Environmental Information/NOAA
  • Lawrimore, Jay
    National Centers for Environmental Information/NOAA
Publishers
  • NOAA National Centers for Environmental Information
Theme keywordsGlobal Change Master Directory (GCMD) Science Keywords
  • Earth Science > Climate Indicators
  • Earth Science > Atmosphere > Atmospheric Temperature > Surface Temperature > Air Temperature
  • Earth Science > Atmosphere > Precipitation > Precipitation Amount
Global Climate Observing System (GCOS) Essential Climate Variables (ECVs)
  • Atmospheric - Surface - Air Temperature
  • Atmospheric - Surface - Precipitation
Keyword Thesaurus Title
  • Normals
Data Center keywordsGlobal Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
Place keywordsGlobal Change Master Directory (GCMD) Location Keywords
  • Continent > North America > United States Of America
  • Ocean > Pacific Ocean > Central Pacific Ocean
Data Resolution keywordsGlobal Change Master Directory (GCMD) Horizontal Data Resolution Keywords
  • Point Resolution
Global Change Master Directory (GCMD) Vertical Data Resolution Keywords
  • Point Resolution
Stratum keywordsGlobal Change Master Directory (GCMD) Location Keywords
  • Vertical Location > Land Surface
Use Constraints
  • Cite as: Palecki, Michael; Durre, Imke; Applequist, Scott; Arguez, Anothony; Lawrimore, Jay. 2021: U.S. Climate Normals 2020: U.S. Hourly Climate Normals (1991-2020). [indicate subset used]. NOAA National Centers for Environmental Information. https/doi.org/{{DOI}}. Accessed [date].
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Access Constraints
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Lineage StatementThe Monthly Normals are generated from Global Historical Climatology Network Monthly V.4 and Daily V.3 using Fortran software routines developed for the 1981-2010 normals production and updated for technical improvements.
Processor
  • NOAA National Centers for Environmental Information
Processing Steps
  • 2023-05-15T00:00:00 - The main body of 1991-2020 U.S. Climate Normals were produced in 2021. However, since then a small number of requests have been received from our primary partner, the National Weather Service, for some station normals to be recalculated or added to the compilation of station normals. Reasons for these recalculations vary, but are usually accompanied by one of two causes. Either there is a correction of a flagging situation that caused a previously calculated normal to be rejected by internal quality control, or a significant amount of the underlying observational data has been replaced or added to a station record. Normals calculations follow the same procedures as used in the main production run. These new stations normals files are then tarred with the existing normals files, or used to replace existing normals files as necessary. All existing station normals that have not been replaced are carried over into Version 1.0.1.
Processing EnvironmentThe input files are available in an ascii format, piped to scripts and programs on normalswork-dev, and completed as *.csv files in bulk variable storage and station file storage formats. They are then validated and quality controlled, and shipped to climon-prod for shipping to archive directories and online storage directories.
Last Modified: 2023-08-10
For questions about the information on this page, please email: ncei.info@noaa.gov