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

Accumulated 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.

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].

Dataset Identifiers

NCE DSI: 2049_01
gov.noaa.ncdc:C01620

ISO 19115-2 Metadata

C01620

XML


Search Data	NCEI Common Access (search) Search for data via the interface
Download Data	NCEI Direct Download (Dataset Files) (download) Direct download for the dataset. Normals Monthly 1991-2020 PDF Sample (download) This sample data file shows how the data are formatted in PDF and is for example purposes only. Normals Monthly 1991-2020 CSV Sample (download) This sample data file shows how the data are formatted in CSV and is for example purposes only. AWS S3 Explorer (Region: us-east-1) (download) Browse view to explore the S3 bucket.
Distribution Formats	CSV (Version: 1.0)
Ordering Instructions	Contact NCEI for other distribution options and instructions.
Distributor	NOAA 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 Period	1991-01 to 2020-12 (time interval: 1-month)
Spatial Reference System	urn: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	NCEI Dataset Landing Page Landing page for the dataset. NCEI Product Information Page Description of the data and related resources. Normals Daily Documentation 1991-2020 Normals User Guide that provides product descriptions and formats for all data and products produced and made available to users. Normals Calculation Methodology 2020 The science and methodologies used to generate official climate normals for the United States. Readme By-Variable By-Station Normals File This document describes the technical layout of the CSV normals files in both the individual, by-station, format and the grouped by-variable format. It also provides a guide to the location of the variables within the larger by-variable tar files. Registry of Open Data on AWS Information on AWS data access. Azure Landing Page (Region: us-east) Information on Microsoft Azure data access.
Associated Resources	NOAA'S 1981-2010 U.S. CLIMATE NORMALS An Overview NOAA'S 1981-2010 U.S. CLIMATE NORMALS An Overview Paper DOI NOAA's 1981-2010 U.S. Climate Normals: Monthly Precipitation, Snowfall, and Snow Depth NOAA's 1981-2010 U.S. Climate Normals: Monthly Precipitation, Snowfall, and Snow Depth Paper DOI U.S. Gridded Climate Normals NCEI web page for the U.S. Gridded Climate Normals Related dataset web page with general information and access links for that dataset. 1981–2010 U.S. Climate Normals NCEI web page for the 1981–2010 U.S. Climate Normals Related dataset web page with general information and access links for that dataset.

General Documentation

NCEI Dataset Landing Page
Landing page for the dataset.
NCEI Product Information Page
Description of the data and related resources.
Normals Daily Documentation 1991-2020
Normals User Guide that provides product descriptions and formats for all data and products produced and made available to users.
Normals Calculation Methodology 2020
The science and methodologies used to generate official climate normals for the United States.
Readme By-Variable By-Station Normals File
This document describes the technical layout of the CSV normals files in both the individual, by-station, format and the grouped by-variable format. It also provides a guide to the location of the variables within the larger by-variable tar files.
Registry of Open Data on AWS
Information on AWS data access.
Azure Landing Page (Region: us-east)
Information on Microsoft Azure data access.

Associated Resources

NOAA'S 1981-2010 U.S. CLIMATE NORMALS An Overview
- NOAA'S 1981-2010 U.S. CLIMATE NORMALS An Overview
  Paper DOI
NOAA's 1981-2010 U.S. Climate Normals: Monthly Precipitation, Snowfall, and Snow Depth
- NOAA's 1981-2010 U.S. Climate Normals: Monthly Precipitation, Snowfall, and Snow Depth
  Paper DOI
U.S. Gridded Climate Normals
- NCEI web page for the U.S. Gridded Climate Normals
  Related dataset web page with general information and access links for that dataset.
1981–2010 U.S. Climate Normals
- NCEI web page for the 1981–2010 U.S. Climate Normals
  Related dataset web page with general information and access links for that dataset.


Publication Dates	publication: 2023-05-15
Edition	1.0.1
Data Presentation Form	Digital document - digital representation of a primarily textual item (can contain illustrations also)
Dataset Progress Status	Complete - production of the data has been completed
Data Update Frequency	As needed
Purpose	NOAA 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 keywords	Global 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 keywords	Global Change Master Directory (GCMD) Data Center Keywords DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
Place keywords	Global Change Master Directory (GCMD) Location Keywords Continent > North America > United States Of America Ocean > Pacific Ocean > Central Pacific Ocean
Data Resolution keywords	Global Change Master Directory (GCMD) Horizontal Data Resolution Keywords Point Resolution Global Change Master Directory (GCMD) Vertical Data Resolution Keywords Point Resolution
Stratum keywords	Global 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.

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 Statement	The 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 Environment	The 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