Help

What this viewer shows

This application visualizes climate metrics over Canada as gridded fields, with optional overlays (hydrometric gauges and dam inventories).
Use the sidebar to select a variable, warming level, and summary statistic (where available).

Quick start (recommended workflow)

1. Projection: Choose Equirectangular (fast; geographic lon/lat) or Orthographic (globe view; heavier).
2. Stride: Start with 2 for fast exploration. Switch to 1 for full resolution when finalizing a figure.
3. Variable: Select Precipitation, CIF, or a Design variable.
4. Warming level: Choose the Global Warming Level (°C) to display.
5. Metric / Statistic: Pick the metric and (for ensemble) the statistic (Mean/Median/Q25/Q75).

Only one gridded layer is shown at a time (the most recent active selection).

Controls and interpretation

Projection

• Equirectangular: longitude/latitude view; best for locating features and most comparisons.
• Orthographic: globe view; useful for presentation but slower due to reprojection.

Stride (performance vs detail)

• Stride = 1: plot every grid cell (highest detail; slowest).
• Stride = 2 or 3: decimated plotting for fast interaction (recommended while exploring).

Colour mapping

• Value-based: uses the variable’s native values and units.
• Quantile/Decile: emphasizes spatial rank rather than absolute magnitude.
  • Continuous gradient: maps percentiles to a smooth 0–100% colorbar.
  • Discrete bands: bins values into percentile classes (see below).

Discrete quantile legend definitions

• 5 classes: 0–20%, 20–40%, 40–60%, 60–80%, 80–100%
• 6 classes (robust): 0–2%, 2–25%, 25–50%, 50–75%, 75–98%, 98–100%
• 10 classes: 0–10%, 10–20%, …, 90–100%

Overlays

• Gauges: enable Show gauge locations to display gauge positions.
  If a gauge dataset is selected, marker colours represent the chosen return-level quantile.
• Dams:
  • Ontario dam inventory: Ontario-only points.
  • GDAT inventory: national selection points.

Extracting values at a point (two methods)

The viewer supports two equivalent ways to specify a point of interest.
In both cases, you must click Record point to generate the table.

Method 1 — Manual latitude/longitude input

1. Open Map → Point Selector.
2. Enter Latitude and Longitude under Manual point input.
3. Click Record point.

Method 2 — Click-to-select on the map

1. Open Map → Point Selector.
2. Ensure Click on map to set manual Lat/Lon is enabled.
3. Click on the map; the Latitude/Longitude fields update automatically.
4. Click Record point.

Notes:

• Click-to-select is active only when a gridded layer is displayed (i.e., a variable is selected and the map is “filled”).
• In Orthographic projection, clicks are converted from projected coordinates back to lon/lat internally; the recorded point is always lon/lat.

Where the extracted values appear

Table tab (interactive view)

After you click Record point, the extracted values appear under:
Table → Selected point – ensemble “Mean” values.

The header shows the selected lon/lat and the nearest grid indices (rlat/rlon) used for sampling.

Downloads tab (CSV export)

Download the most recent extracted table from:
Downloads → Download point table (CSV)

The CSV always corresponds to the most recently recorded point.

Tips

• Start with Equirectangular + Stride 2 for responsive exploration.
• If the field looks “washed out”, try Quantile mapping to reveal spatial structure.
• Use Value-based when you need physically interpretable magnitudes and units.

Known limitations

• Some variables have missing values over parts of Canada; these appear as blank/transparent regions.
• Orthographic mode is more computationally expensive due to reprojection and resampling.

Contact Us

We welcome your feedback and questions regarding the Canada Climate Viewer.

Developed in partnership with the National Research Council of Canada (NRC)

Email: mnajafi7@uwo.ca

Principal Investigator
M. Reza Najafi, PhD, P.Eng.
Professor, Department of Civil and Environmental Engineering (CEE)
HydroClimEx Lab, Western University
London, Ontario, Canada

NRC Technical Lead
Hamidreza Shirkhani, PhD
National Research Council Canada (NRC)
Hamidreza.Shirkhani@nrc-cnrc.gc.ca

Webtool development:
Afshin Shaygani, PhD (former Postdoctoral Fellow) HydroClimEx Lab

Data:
Jack W. Warden
HydroClimEx Lab

Acknowledgement:
This project was supported by the Climate Resilient Built Environment (CRBE) Initiative, funded by Housing, Infrastructure and Communities Canada (HICC).

About Canada Climate Viewer

Version: 0.9 Beta (2026)

Technical Overview & Performance

The Canada Climate Viewer is a specialized high-performance visualization tool designed to handle large-scale national hydro-climatic datasets. It is engineered to provide near-instantaneous interactivity for complex spatial data through a multi-tiered optimization strategy:

• Optimized Data Transfer: Implements orjson serialization for high-speed data transmission between the server and the browser.
• Hardware Acceleration: Automatically switches to WebGL rendering for high-density layers to maintain smooth responsiveness.

Developed by:
Afshin Shaygani, PhD (former Postdoctoral Fellow) HydroClimEx Lab

Data Provision:
Jack W. Warden
HydroClimEx Lab, Western University

Data Sources

Data presented through the Canada Climate Viewer were compiled or derived from the following datasets, models, and publications:

• Climate projections and indices: Climate projections were derived from the Ouranos CRCM5-CMIP6 ensemble. Climate indices were calculated for individual simulations on the model’s native grid and summarized by warming level using ensemble statistics (Paquin et al., 2025).

• Global dam information: Nationwide locations of large dams were obtained from Version 1 of the Global Dam Tracker (GDAT) dataset (Zhang & Gu, 2023).

• Ontario dam information: Ontario dam locations and attributes were obtained from the Ontario Dam Inventory, published by the Ontario Ministry of Natural Resources and Forestry through Land Information Ontario (Ontario Ministry of Natural Resources and Forestry, 2020).

• Gauge-location hydrologic data: Modelled hydrologic and streamflow data at gauge locations were generated using the WRF-Hydro® Modeling System (Gochis et al., 2020).

• Compound inland flooding: Compound inland flooding data were derived from the rain-on-snow and saturation-excess flooding analyses presented by Fereshtehpour et al. (2025).

References

Paquin, D., McCray, C. D., Gauthier, C. B., Giguère, M., Asselin, O., Bourgault, P., Labonté, M.-P., & Matte, D. (2025). The Ouranos CRCM5-CMIP6 ensemble: A dynamically downscaled ensemble of CMIP6 simulations over North America. Scientific Data, 12, 1984.

Zhang, A. T., & Gu, V. X. (2023). Global Dam Tracker: A database of more than 35,000 dams with location, catchment, and attribute information (Version 1) [Data set]. Zenodo.

Ontario Ministry of Natural Resources and Forestry. (2020). Ontario Dam Inventory [Data set]. Land Information Ontario, Government of Ontario.

Gochis, D. J., Barlage, M., Cabell, R., Casali, M., Dugger, A., FitzGerald, K., McAllister, M., McCreight, J., RafieeiNasab, A., Read, L., Sampson, K., Yates, D., & Zhang, Y. (2020). The WRF-Hydro® Modeling System Technical Description, Version 5.1.1. National Center for Atmospheric Research.

Fereshtehpour, M., Najafi, M. R., & Cannon, A. J. (2025). Characterizing compound inland flooding mechanisms and risks in North America under climate change. Earth’s Future, 13(2), e2024EF005353.

No Warranty and Limitations of Liability

The data and information provided through Canada Climate Viewer are made available on an “AS IS” basis and without any warranty or representation of any kind, whether express or implied, including but not limited to warranties of accuracy, completeness, reliability, fitness for a particular purpose, or non-infringement

Use of this tool and any reliance placed on the data or derived information is entirely at the user’s own risk. The project team and affiliated institutions make no guarantees regarding the applicability of the outputs to any specific engineering, regulatory, operational, or decision-making context.

To the fullest extent permitted by law, The University of Western Ontario, and The NRC shall not be liable for any loss, damage, or injury of any kind arising from the use of, or reliance upon, the information provided by this tool, including but not limited to direct, indirect, incidental, consequential, or special damages.

Nothing in this statement limits the responsibility of users to exercise appropriate professional judgment or to comply with applicable codes, standards, regulations, and legal requirements.

Data Index Reference

The tool computes indices for each CRCM5 ensemble member on the native grid, summarized using ensemble statistics for each warming level. Units are reported as either multiplicative change factors (PerChg) or additive changes in base units (e.g., Δdays, ΔdegC).

1. Extreme Precipitation Return Levels (GEV)

2. Annual Precipitation Totals & Maxima

3. Freeze–Thaw Cycles (Surface)

4. Extreme Temperature Range (ETR)

5. Degree-Days & Mean Temperature

6. Wet & Dry Spell Duration

7. Precipitation Frequency & Intensity

8. Percentile-Based Extreme Precipitation

9. Compound Inland Flooding