Overview

The daily climate records database, also known as Long Term Climate Extremes (LTCE), was developed to address the fragmentation of climate information due to station changes (opening, closing, relocation, etc.) over time. For approximately 750 locations in Canada, "virtual" climate stations have been developed by joining (threading) climate data for an urban location, from nearby stations to make long-term records. For each long-term record, the extremes (record values) of daily maximum/minimum temperatures, total precipitation and snowfall for each day of the year were identified. This dataset identifies, for example, the greatest precipitation over the record for each day of the year for the selected area (e.g., the greatest daily precipitation recorded in the Tuktoyaktuk area for July 30th was 9.4 mm and was reached in 1964).

Provider's contact information

Environment and Climate Change Canada

ec.climatatlantique-climateatlantic.ec@canada.ca

Licensing

Open Government Licence - Canada.

Variable name and units:

Greatest daily precipitation (mm)

Spatial coverage and resolution:

Canada, point locations.

Temporal coverage and resolution:

The data is available for each day of the year. The record value over the entire recorded period and the year when the record was reached are provided.

The data will continue to be updated regularly.

Information about observations (number, homogeneity)

The following table presents the number of stations per region and variable

Methodology

The dataset was developed using daily values from MSC stations. For climate stations operating on a 24-hour basis, since July 1, 1961, the climatological day for precipitation (as for temperature) ends at 0600Z of the next day. From June 1, 1957, to June 30, 1961, the climatological day for precipitation (and maximum temperature) ended at 1200Z of the next day. Before June 1, 1957, the climatological day for precipitation and maximum temperature ended at 1230Z of the next day.

At locations with no hourly observations, observation times are generally morning and evening local time. In general, the climatological day for precipitation (and maximum temperature) ends at the morning observation of the next day. For sites reporting only once per day, the calendar day rather than climatological day applies.

Each of the City Page locations of weather.gc.ca has a Virtual climate station. A virtual climate station is the result of threading (joining) together climate data from nearby current and historical stations to build a long-term dataset. All available data within a 20 km radius of each urban center was searched and catalogued (some latitude was permitted to include data which was close to the 20 km cut-off during the subjective review stage). The starting point is a representative, currently active station in the area of the urban center. These data were followed backward in time until it was no longer available or until it was replaced by a higher quality dataset from the same station. When the earliest or end point of a thread fragment was reached, an alternate from the catalogue was chosen, keeping in mind data quality, proximity to the prior station and any gaps in data length. This process was repeated until the thread extended back in time as far as possible.

In a small percentage of cases where there is no currently active climate station within 20 km of the urban center, an alternate station may have been chosen from representative stations at a maximum radius of 35 km.

Information about the technical and scientific quality

This dataset represents summaries of Environment and Climate Change Canada’s official station observations.

Limitations and strengths for application in North Canada

Observations are sparse in the northern Canada and the records have missing data.

References to documents describing the methodology or/and the dataset

Technical documentation

Frequently asked questions about long term climate extremes for Canada

Link to download the data and format of data:

Map based extraction tool: GeoJSON and CSV on CCCS/ECCC: https://climate-change.canada.ca/climate-data/#/daily-climate-records

Publications including dataset evaluation or comparison with other data in northern Canada

There are no publications that evaluate this dataset in northern Canada.