The National Centers for Environmental Information (NCEI) is the branch of the National Oceanic and Atmospheric Administration (NOAA) responsible for archiving and providing public access to the United States’ official long-term record of weather, climate, coastal, and ocean data. For researchers working with historical climate observations, ocean measurements, or geophysical datasets, NCEI functions the way a large domain repository is meant to: as the durable, authoritative home for data that individual projects and instruments cannot preserve on their own. This guide covers what NCEI is, what it holds, how to actually retrieve data from it, and how it differs from data-rescue work aimed at recovering at-risk records.
What Is NCEI?
NCEI was formed in 2015 through the merger of three previously separate NOAA data centers: the National Climatic Data Center (NCDC), the National Geophysical Data Center (NGDC), and the National Oceanographic Data Center (NODC), the last of which included the National Coastal Data Development Center (NCDDC). NOAA consolidated the three centers to apply consistent data stewardship practices across atmospheric, geophysical, coastal, and oceanic science rather than maintaining separate archives, systems, and access points for each discipline. NCEI describes itself as providing environmental data “from the depths of the ocean to the surface of the sun,” and by its own account its archive now holds more than 60 petabytes of data — among the largest active environmental-data holdings of any single archive in the world.
From Three Legacy Centers to One Archive
Each of the three predecessor centers had its own long institutional history before the merger:
- National Climatic Data Center (NCDC) — established in 1934 and historically the world’s largest active archive of weather data, headquartered in Asheville, North Carolina, where NCEI’s main campus remains today.
- National Geophysical Data Center (NGDC) — formed in 1965 under the Environmental Science Services Administration (NOAA’s direct predecessor), headquartered in Boulder, Colorado, and responsible for geophysical, geomagnetic, and solar-terrestrial data.
- National Oceanographic Data Center (NODC) — established in 1961 and transferred into NOAA when the agency was created in 1970, headquartered in Silver Spring, Maryland, and responsible for oceanographic and coastal data.
Researchers who worked with any of these agencies before 2015 will still see their names referenced in older citations, dataset documentation, and legacy URLs; NCEI is the direct institutional successor to all three, and data originally archived under NCDC, NGDC, or NODC is now accessed through NCEI’s systems.
What Data NCEI Hosts
NCEI is organized internally around several science divisions, and its holdings span a wide range of environmental domains, including:
- Climate and weather data — historical surface weather observations, climate normals, the Global Historical Climatology Network (GHCN) station records, radar data, and NOAA’s Climate Data Records (CDRs), which are long-term, consistently reprocessed satellite-derived climate variables.
- Ocean and coastal data — oceanographic profiles, sea surface temperature, water-level and tide-gauge records from the National Water Level Observation Network (NWLON) and Physical Oceanographic Real-Time System (PORTS), and coastal bathymetry.
- Geophysical data — geomagnetic, gravity, and solar-terrestrial data inherited from the former NGDC, including space-weather observations.
- Satellite data — archived imagery and products from NOAA’s polar-orbiting and geostationary satellite programs, including GOES data.
- Paleoclimatology and long-term proxy records, elevation and digital elevation models, and a range of derived summary products such as the Global Summary of the Month (GSOM) and Global Summary of the Year (GSOY).
Because NCEI’s scope spans so many disciplines, it is worth checking NCEI’s own dataset search rather than assuming a given variable, station, or region isn’t covered — the practical difficulty for most researchers is less “does NCEI have this” and more “which of NCEI’s several access tools is the right entry point.”
How Researchers Access NCEI Data
NCEI does not use a single unified portal; it offers several access tools suited to different use cases, and knowing which one fits your task saves considerable time.
Climate Data Online (CDO)
Climate Data Online is NCEI’s primary interface for station-based weather and climate data — daily and monthly summaries, climate normals, and historical observations by station or region. It supports both a web search interface for one-off lookups and a token-based Web Services API for programmatic, repeated queries, which is the more practical route for anyone pulling data into a script or analysis pipeline rather than downloading files by hand.
NCEI Data Access tools and APIs
For bulk and programmatic access more broadly, NCEI provides a set of cloud-ready Data Access APIs alongside Search and Order APIs, direct downloads in formats such as CSV, shapefile, and PDF, and dataset-subsetting capabilities so a researcher can request only the variables, stations, or time range actually needed rather than an entire dataset.
NOAA OneStop
NOAA OneStop is NCEI’s cross-disciplinary discovery layer, searching across roughly 100,000 dataset collections and several million metadata records spanning NOAA’s full data holdings, not just NCEI’s. It is the better starting point when a researcher isn’t sure which specific dataset or division holds the data they need and wants to search by keyword, geography, time range, or format across NOAA as a whole.
Order and archive requests
Some older or less-digitized holdings — particularly historical records inherited from the legacy NCDC, NGDC, and NODC archives — are not fully available through self-service download and instead require submitting a data or imagery order directly to NCEI. This is most common for older paper, microfilm, or specialty datasets that have not yet been digitized for open online access.
NCEI’s Role as US Environmental-Data Infrastructure
NCEI functions as foundational, general-purpose infrastructure for US environmental science in a few concrete ways. It is the official archival home for NOAA’s weather and climate observations, meaning that many downstream products — from NOAA’s own Billion-Dollar Weather and Climate Disasters accounting to international climate assessments — trace their underlying data back to NCEI’s archive. Many NCEI datasets are assigned a DOI, allowing researchers to cite the exact dataset and version used in a publication rather than citing NCEI generically, which matters for reproducibility in the same way that citing a specific software release matters more than citing a project by name alone. NCEI is also listed as a domain repository in the re3data registry of research data repositories, and has participated as a member node in federated data networks such as DataONE, which is how researchers using cross-repository discovery tools can find NCEI-held datasets alongside holdings from other earth-science archives. For research administrators building or reviewing a data management plan that names a federal climate or ocean repository, NCEI is generally a defensible choice precisely because of this institutional durability: it is a permanent federal archive rather than a project-funded repository that could lose support at the end of a grant.
NCEI Access vs. Data Rescue Projects: Two Different Things
CASRAI’s guide to data rescue projects covers a related but distinct topic: organized efforts to recover, digitize, and preserve environmental and scientific data that is genuinely at risk of being lost — degrading paper records, obsolete storage media, or datasets facing removal from public access. Routine NCEI access, covered in this guide, is the ordinary case: retrieving already-archived, already-accessible data from NOAA’s standing infrastructure through Climate Data Online, the Data Access APIs, or NOAA OneStop. Data rescue becomes relevant to NCEI specifically when older, not-yet-digitized holdings inherited from the legacy NCDC, NGDC, and NODC archives are the subject of a rescue or digitization effort; day-to-day retrieval of an already-digitized climate or ocean dataset is not a data-rescue activity and doesn’t require the safeguards that guide describes.
Practical Tips for Researchers
- Cite the specific dataset and version, using its DOI where one is assigned, rather than citing “NOAA NCEI” generically — this matters for anyone else trying to reproduce your analysis with the same underlying data.
- Check dataset documentation and metadata before analysis; NCEI datasets vary in temporal coverage, spatial resolution, quality-control level, and units, and the documentation accompanying each dataset specifies these details.
- Use CDO for station-level lookups, the Data Access APIs for programmatic/bulk retrieval, and OneStop when you’re not yet sure which specific dataset you need — picking the tool that matches the task avoids a lot of wasted searching.
- Expect a request-based workflow for some legacy or specialty holdings that are not yet available through self-service download.
- Note that a data management plan naming NCEI as a repository should still describe how a specific dataset was deposited or retrieved, since NCEI’s own submission and access processes vary by data type and division.
Frequently Asked Questions
Is NCEI data free to access?
Yes. NCEI’s public archive is freely accessible; there is no subscription or paywall for the standard datasets available through Climate Data Online, the Data Access APIs, or NOAA OneStop. Some older or specialty holdings requiring a manual order may involve processing time rather than a fee.
What is the difference between NCEI and the National Weather Service (NWS)?
The NWS is NOAA’s operational forecasting and warning arm, focused on current and near-term weather. NCEI is NOAA’s long-term archive: it is where historical weather, climate, and ocean data ends up once it moves past operational use, and where researchers go for historical records rather than current forecasts.
How far back does NCEI’s data go?
Coverage varies enormously by dataset and data type. Some station-based weather records extend back well over a century, while satellite-derived climate records are necessarily limited to the satellite era (generally from the late twentieth century onward), and some legacy oceanographic archive holdings date back further still. There is no single answer across all of NCEI’s holdings; check the specific dataset’s documented period of record.
Do I need to request permission to use NCEI data in a publication?
No formal permission process is required for standard public NCEI data; it is US federal government data and generally not subject to copyright restriction in the way commercially licensed data can be. Researchers should still cite the specific dataset and, where assigned, its DOI.
Is NCEI the right repository to name in a data management plan?
For climate, weather, ocean, or geophysical data that fits its scope, yes — NCEI is a stable, federally maintained domain repository, which is generally the kind of long-term guarantee funders look for in a DMP’s data-sharing and preservation section. It is not a generalist repository for arbitrary research data outside its environmental-science scope; data outside that scope needs a different repository.
How is this different from CASRAI’s data rescue projects guide?
That guide covers organized efforts to recover data that is genuinely at risk of being lost — degrading records, obsolete formats, or data facing removal from public access. This guide covers the routine case: how to retrieve data that is already safely archived and accessible through NCEI’s standing access tools.
