GHCNm

Explore the NOAA Global Historical Climatology Network monthly (GHCNm) dataset with an interactive Climate Explorer dashboard.

NOAA GHCNm overview

This dashboard explores the Global Historical Climatology Network Monthly (GHCNm) dataset, which provides quality-controlled historical monthly meteorological data and meteorological observations from weather stations worldwide. Curated by NOAA/NCEI, this dataset is a cornerstone for monitoring global climate change and analyzing long-term climate trends. The current v4 release blends monthly mean temperature and precipitation statistics, adds automated homogenization, and continues to receive new updates from active stations.

Global Data Coverage

Looking for data for your country?
This dataset contains meteorological records for every country in the world. If you do not see a dedicated dashboard for your specific region elsewhere on Climate Explorer, you will find the data here.

Why this dataset matters

  • Provides a globally consistent baseline for comparing climate signals between continents, regions, or single stations.
  • Offers homogenized series that correct for instrument changes, relocations, and reporting gaps, which is crucial for long-term trend detection.

Coverage and refresh cadence

GHCNm v4 currently spans 1750 to present (station dependent). New station files are ingested monthly, with NOAA applying additional quality flags before publication. Climate Explorer ingests the public release within a few days to keep the explorer synchronized with the upstream reference archive.

Use the interactive explorer

Interact with the web app to discover individual stations, compare anomalies, or export CSV summaries. Use the panel controls to filter by variable, anomaly baseline, and map region.

About this Data

The GHCNm (Global Historical Climatology Network Monthly) is the world’s primary baseline dataset for long-term climate analysis. Maintained by NOAA NCEI (National Centers for Environmental Information), this massive archive aggregates quality-controlled observations from over 20 global data sources, including the WMO Information System and various national meteorological archives.

Through Climate Explorer, you gain streamlined access to this global network without needing to parse complex text files. The data facilitates:

  • Global Climate Monitoring: Tracking temperature anomalies and precipitation patterns across continents.
  • Long-term Trend Analysis: Investigating climate change signals, warming trends, and decadal variability.
  • Regional Climate Assessment: Evaluating historical weather patterns with worldwide ground-truth data.

Unique Value: Every Country, One Interface

Most climate datasets are fragmented by national borders. GHCNm unifies them. Whether you are analyzing monsoon trends in India, winter storms in Canada, or heat stress in Australia, this explorer provides a consistent interface for every country in the world.

The dataset features monthly resolution, which is critical for capturing long-term climate trends and historical variability that daily data might obscure or be too noisy for.

How to use this tool

  1. Global Navigation: The map starts with a global view. Click on any blue dot to select a station.
  2. Filter by Country: Use the sidebar dropdown to instantly zoom into a specific nation’s network (e.g., “United Kingdom”, “Brazil”, “South Africa”).
  3. Adjust Time Window: The dashboard loads the full available history (1750 to present). Use the Year Range slider to focus on specific decades or centuries.
  4. Visualize & Export:
    • Plots: Inspect the anomaly charts to visualize deviations from the long-term mean.
    • Data: Switch to table view to download the raw CSV data for your research.

Need more help? View the full About page for contact information.

Data source and code

Source material and citation

  • Official NOAA documentation for the dataset is available through the NCEI GHCNm landing page.
  • When referencing results, cite NOAA/NCEI as the data originator and include the Climate Explorer URL so readers can reproduce the visualization workflow.
  • For methodology details, consult the v4 technical note and quality-control addenda included on the official download page.