LTCE

1. Overview of LTCE

• Purpose: Address fragmentation in climate records due to station changes (relocation, opening, closure, etc.).

• Scope: Provides a continuous climate dataset for 750+ urban locations in Canada.

• Data Coverage:

  • Earliest records: From the 1800s (for some stations).

  • Latest records: Up to present day.

• Variables Tracked:

  • Daily extreme temperatures:

    • Highest Maximum Temperature (°C)

    • Highest Minimum Temperature (°C)

    • Lowest Maximum Temperature (°C)

    • Lowest Minimum Temperature (°C)

  • Precipitation Extremes:

    • Greatest Precipitation (mm)

  • Snowfall Extremes:

    • Greatest Snowfall (cm)

• Spatial Resolution:

  • Point locations across Canada.

  • Threaded stations within a 20 km search radius (extended to 35 km in rare cases).

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2. Dataset Construction Methods

2.1 Observational Data Sources

• Multiple climate stations were merged into "virtual" climate stations to extend data records.

• Observation Times:

  • After 1961: Climate day ends at 0600Z (UTC) of the next day.

  • 1957–1961: Ends at 1200Z for max temperature and precipitation, 0000Z for min temperature.

  • Before 1957: Ends at 1230Z for max temperature and precipitation, 0030Z for min temperature.

• Manual vs. Automated Stations:

  • Older stations report once daily (calendar-based).

  • Modern stations report hourly, improving data accuracy.

2.2 Threading Methodology

• Threading = Combining climate records from different stations within a 20 km radius.

• If no active stations exist within 20 km, stations up to 35 km were used.

• Selection Criteria:

  • Data quality

  • Station proximity

  • Completeness of records

• Manual verification by climate experts ensured accuracy.

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3. Data Variables and Technical Details

3.1 Temperature Extremes

Variable	Description	Unit
Highest Maximum Temperature	Hottest recorded daily temperature	°C
Highest Minimum Temperature	Warmest nighttime low temperature	°C
Lowest Maximum Temperature	Coldest daytime high temperature	°C
Lowest Minimum Temperature	Coldest nighttime temperature	°C

3.2 Precipitation and Snowfall Extremes

Variable	Description	Unit
Greatest Precipitation	Most rainfall in a single day	mm
Greatest Snowfall	Most snow accumulation in a single day	cm

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4. Data Applications

4.1 Use Cases

• Urban Planning: Helps cities design climate-resilient infrastructure.

• Extreme Weather Analysis: Identifies historical trends in heatwaves, cold waves, and heavy precipitation.

• Energy & HVAC Planning: Determines heating/cooling demand based on extreme temperatures.

• Disaster Risk Management: Supports flood forecasting and emergency response planning.

• Agriculture: Assists in crop viability assessment based on temperature and precipitation extremes.

4.2 Limitations

• Not designed for climate change analysis – unadjusted for long-term climate shifts.

• Data gaps exist where stations were inactive or unavailable.

• Manual threading may introduce subjectivity, despite expert review.

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5. Data Access and Resources

• API Access for LTCE Stations:

  • Temperature Stations List

  • Precipitation Stations List

  • Snowfall Stations List

• Full Dataset:

  • Climate Data Archive

  • Homogenized Climate Data for Trends

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6. Conclusion

The LTCE dataset provides historical daily extremes for temperature, precipitation, and snowfall, offering a unique long-term perspective on Canada's climate variability. While not suitable for climate change trend analysis, it is an essential tool for extreme event planning, infrastructure resilience, and risk assessment.