Canadian Homogenized Surface Air Temperature (CanHomT V4)
This fourth generation homogenized daily (CanHomT dlyV4), and monthly (CanHomT mlyV4) surface air temperature dataset provides daily maximum, minimum and mean temperatures as well as monthly, seasonal, and annual means of these variables, for 651 long-term stations across Canada. The procedures used to produce the dataset and to estimate long-term trends over the 1948-2023 period are detailed in Wan et al. (2025). The fourth generation of CanHomT includes two main improvements over the third generation (Vincent et al., 2020): First, an adjustment for the cold bias in daily minimum temperatures, caused by an inadequate observing window defined by the climatological day since July 1, 1961, is now applied to all stations with both daily and hourly temperature observations, including all automatic stations. Second, missing daily and monthly values, including longer gaps, were filled using the ANUSPLIN surface temperature estimates. Station data records that began later than 1948 were infilled back to 1948 for monthly data, and 1949 for daily data. In addition to these main improvements, the original data were quality controlled using more comprehensive procedures than in previous generations. To form long-term series, most station records were joined with data from nearby stations, and all 651 stations are active as of 2023. An inhomogeneity test procedure, both with and without the use of reference series methods, was applied to detect non-climatic shifts in the monthly series. A quantile-matching procedure was then used to adjust the identified inhomogeneities in the daily and monthly series. This dataset enhances the reliability and the temporal and spatial continuity of observed temperature records in Canada, enabling more precise assessments of long-term climate trends.
References:
Vincent, L. A., M. M. Hartwell, and X. L. Wang, 2020: A third generation of homogenized temperature for trend analysis and monitoring changes in Canada’s climate. Atmosphere-Ocean., 58:3, 173-191, doi:10.1080/07055900.2020.1765728.
Wan, H., A. C., Spassiani & L. A. Vincent, 2025: Canada’s fourth generation of homogenized surface air temperature and its trends for 1948-2023. Atmosphere-Ocean, DOI: 10.1080/07055900.2025.2516796.
Datasets available for download
Additional Info
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| Last Updated | October 20, 2025, 02:15 (UTC) |
| Created | October 20, 2025, 02:15 (UTC) |
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Domain / Topic
Domain or topic of the dataset being cataloged.
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Title
Title for the Dataset.
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Canadian Homogenized Surface Air Temperature (CanHomT V4) |
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Description
A description of the dataset.
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This fourth generation homogenized daily (CanHomT dlyV4), and monthly (CanHomT mlyV4) surface air temperature dataset provides daily maximum, minimum and mean temperatures as well as monthly, seasonal, and annual means of these variables, for 651 long-term stations across Canada. The procedures used to produce the dataset and to estimate long-term trends over the 1948-2023 period are detailed in Wan et al. (2025). The fourth generation of CanHomT includes two main improvements over the third generation (Vincent et al., 2020): First, an adjustment for the cold bias in daily minimum temperatures, caused by an inadequate observing window defined by the climatological day since July 1, 1961, is now applied to all stations with both daily and hourly temperature observations, including all automatic stations. Second, missing daily and monthly values, including longer gaps, were filled using the ANUSPLIN surface temperature estimates. Station data records that began later than 1948 were infilled back to 1948 for monthly data, and 1949 for daily data. In addition to these main improvements, the original data were quality controlled using more comprehensive procedures than in previous generations. To form long-term series, most station records were joined with data from nearby stations, and all 651 stations are active as of 2023. An inhomogeneity test procedure, both with and without the use of reference series methods, was applied to detect non-climatic shifts in the monthly series. A quantile-matching procedure was then used to adjust the identified inhomogeneities in the daily and monthly series. This dataset enhances the reliability and the temporal and spatial continuity of observed temperature records in Canada, enabling more precise assessments of long-term climate trends. References: Vincent, L. A., M. M. Hartwell, and X. L. Wang, 2020: A third generation of homogenized temperature for trend analysis and monitoring changes in Canada’s climate. Atmosphere-Ocean., 58:3, 173-191, doi:10.1080/07055900.2020.1765728. Wan, H., A. C., Spassiani & L. A. Vincent, 2025: Canada’s fourth generation of homogenized surface air temperature and its trends for 1948-2023. Atmosphere-Ocean, DOI: 10.1080/07055900.2025.2516796. |
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Metadata Identifier
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Published Date
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2025-06-10 |
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Time Period Data Span (end date)
End date of time data in the dataset.
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Access category
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License
License used to access the dataset.
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Open Government Licence - Canada |
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Limits on use
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Location
Location of the dataset.
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https://open.canada.ca/data/en/dataset/542b90f7-ab39-452c-be5c-2afebdc4724c |
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Data Service
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Owner
Owner of the dataset.
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Environment and Climate Change Canada | Environnement et Changement climatique Canada |
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Contact Point
Who to contact regarding access?
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Government of Canada; Environment and Climate Change Canada; Climate Research Division, [email protected] |
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Contact Point Email
The email to contact regarding access?
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Publisher
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Publisher Email
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[email protected] |
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Author
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Author Email
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Accessed At
Date the data and metadata was accessed.
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Identifier
Unique identifier for the dataset.
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Language
Language(s) of the dataset
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Link to dataset description
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Persistent Identifier
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Globally Unique Identifier
Data is identified by a persistent and globally unique identifier.
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Contains data about individuals
Does the data hold data about individuals?
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Contains data about identifiable individuals
Does the data hold identifiable data about individual?
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Contains Indigenous Data
Does the data hold data about Indigenous communities?
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Platform type of the source portal.
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Version
Version of the datatset
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None |
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Source
Source of the dataset.
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None |
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Version notes
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Is version of another dataset
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Other versions
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Provenance Text
Provenance Text of the data.
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Provenance URL
Provenance URL of the data.
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Temporal resolution
Describes how granular the date/time data in the dataset is.
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GeoSpatial resolution in meters
Describes how granular (in meters) geospatial data is in the dataset.
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GeoSpatial resolution (in regions)
Describes how granular (in regions) geospatial data is in the dataset.
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Indigenous Community Permission
Who holds the Indigenous Community Permission. Who to contact regarding access to a dataset that has data about Indigenous communities.
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Community Permission
Community permission (who gave permission).
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The Indigenous communities the dataset is about
Indigenous communities from which data is derived.
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Number of data rows
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Number of data relations
If RDF dataset, total number of triples.
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Number of data properties
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Data quality
Describes the quality of the data in the dataset.
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Metric for data quality
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