Quality of Historical Climate Data

This web site provides basic access to selected data and locations contained in Environment Canada's database of historical climate data.

This data corresponds to three basic sampling frequencies of climate data collection:

• Hourly data is provided for each hour of the day requested
• Daily data is provided for each day of the month requested
• Monthly data is provided for each month of the year requested

Data collection, processing, quality control checks and procedures have evolved and changed over the years since the earliest data was observed in 1840. Changes have been particular rapid in recent years. For example, the advent of automatic weather observing stations established a new set of challenges for quality control.

The vast majority of observational data is accurate but the database contains some incorrect values, which show up from time to time. Environment Canada continues to review quality control procedures, both as current data is observed and incorporated into the database, and retrospectively for historical data. Be aware that data can be erroneous and that some values may change over time as quality control procedures identify and deal with doubtful data.

Disclaimer

Information presented on this web site is considered public information and may be distributed or copied. An appropriate byline acknowledging Environment Canada is requested.

Environment Canada does not warrant the quality, accuracy, or completeness of any information, data or product from these web pages. It is provided "AS IS" without warranty or condition of any nature. Environment Canada disclaims all other warranties, either expressed or implied, including but not limited to implied warranties of merchantability and fitness for a particular purpose, with respect to the information, data, product or accompanying materials retrieved from this web site.