TRCA Climate Data - Change in Lake Ontario Temperature, Precipitation, and Other Climate Variables
This file is a download link climate variables between 1981-2010 and 1991-2020 reflecting changes in temperature, precipitation, wind, and snow depth changes.
The data can be explored through the WLO Data Explorer, along with other environmental layers.
Project Description
The “Compendium of Coastal Resilience Issues and Typology of Nature-based and Hybrid Solutions” project was supported by the Province of Ontario and the Canada Water Agency.
Stretching between the Niagara River in the south to Cobourg in the east, Western Lake Ontario is home to nearly a quarter of Canada’s population and the fastest growing region in the Great Lakes Basin.
Climate change poses a growing threat to communities and ecosystems along Western Lake Ontario, intensifying existing pressures such as urbanization, land conversion, and legacy contamination.
To help address these challenges, the Land to Lake Initiative was established in 2022 to foster stronger, more coordinated collaborations to enhance capacity for actions that improve water quality and ecosystem health in Western Lake Ontario.
This study supports the objectives of this partnership initiative by:
Broadening understanding of coastal resilience issues affecting this region, and
Identifying and visualizing different types of nature-based and hybrid (or “green-grey”) solutions that can help address these challenges.
For more information about this project, please see our project webpage: https://trca.ca/land-to-lake/issues-solutions-compendium/
Data Description
The Canadian Surface Reanalysis (CaSR, version 3.2, 1980-2024), developed by Environment and Climate Change Canada provides detailed gridded atmospheric and land-surface forcings on a 10 km x 10 km grid, spanning approximately 43 years (1980–2023) with sub-daily and daily temporal resolution. By blending ERA5 global atmospheric data with local observations through the Regional Deterministic Reforecast System (RDRS) and the Canadian Land Data Assimilation System (CaLDAS), it generates critical variables such as 1-hour rainfall and snowfall totals and 3-hour air temperature. This dataset is primarily designed to provide high-quality, consistent inputs for advanced hydrological and surface models. In this study, the daily dataset covering the 1980-2023 time period was extracted to calculate climate variables, reflecting changes in temperature, precipitation, wind, and snow depth changes.
The data was accessed and analyzed from https://hpfx.collab.science.gc.ca/~scar700/rcas-casr/ in April 2026.
Changes in climate variables between 1981–2010 and 1991–2020 are provided as open data. Layers for both time periods are available upon request (see Table 1 for the full list of climate variables available). Please email [email protected].
Table 1. List of climate variables
Climate VariableDescriptionUnitSymbol1 Annual Mean TemperatureMean temperature (°C) is defined as the average of the maximum and minimum temperature at a location for a specified time interval°CTG_YS2 Winter Mean TemperatureWinter months include: December, January, and February (DFJ)°CTG_DJF3 Spring Mean TemperatureSpring months include: March, April, and May (MAM)°CTG_MAM4 Summer Mean TemperatureSummer months include: June, July, and August (JJA)°CTG_JJA5 Fall Mean TemperatureFall months include: September, October, and November (SON)°CTG_SON6 Annual Maximum TemperatureThe average of daily maximum temperatures (°C) at a location for a specified time interval°CTX_YS7 Winter Maximum TemperatureWinter months include: December, January, and February (DFJ)°CTX_DJF8 Spring Maximum TemperatureSpring months include: March, April, and May (MAM)°CTX_MAM9 Summer Maximum TemperatureSummer months include: June, July, and August (JJA)°CTX_JJA10 Fall Maximum TemperatureFall months include: September, October, and November (SON)°CTX_SON11 Annual Minimum TemperatureThe average of daily minimum temperatures (°C) at a location for a specified time interval°CTN_YS12 Winter Minimum TemperatureWinter months include: December, January, and February (DFJ)°CTN_DJF13 Spring Minimum TemperatureSpring months include: March, April, and May (MAM)°CTN_MAM14 Summer Minimum TemperatureSummer months include: June, July, and August (JJA)°CTN_JJA15 Fall Minimum TemperatureFall months include: September, October, and November (SON)°CTN_SON16 Annual Total PrecipitationThe sum of the total rainfall and the water equivalent of the total snowfall (mm) at the location during a specified time intervalmmPR_YS17 Winter Total PrecipitationWinter months include: December, January, and February (DFJ)mmPR_DJF18 Spring Total PrecipitationSpring months include: March, April, and May (MAM)mmPR_MAM19 Summer Total PrecipitationSummer months include: June, July, and August (JJA)mmPR_JJA20 Fall Total PrecipitationFall months include: September, October, and November (SON)mmPR_SON21 Days Below 0°C (Frost Days)The number of days in a year when daily minimum temperature is lower than 0˚C (or < 0˚C). Under these conditions, frost may form on the ground or on cold surfacesdays/yearTN022 Number of Days with Maximum Temperature > 30˚CThe number of days in a year when daily maximum temperature exceeds 30˚C (or > 30˚C)DaysTX3023 Number of Days with Minimum Temperature < -15˚CThe number of days in a year when daily minimum temperature drops below -15˚C (or < -15˚C)DaysTN-1524 Diurnal Temperature RangeDifference between daily maximum and daily minimum air temperature at a location for a specified time interval°CDTR25 Hottest Day Temperature/ Maximum Maximum TemperatureHighest maximum ("day-time") daily air temperature (°C) at a location for a specified time interval°CTXx26 Coldest Day Temperature/ Minimum Minimum TemperatureLowest minimum ("night-time") daily air temperature (°C) at a location for a specified time interval°CTNn27 Simple Daily Intensity IndexAverage intensity (mm/day) over a given period of time, calculated as total wet day precipitation (> 1 mm) divided by the total number of wet daysmm/daySDII28 Near-surface Wind Speed (10m)Average near-surface wind speed (10 m)km/hWIND_YS29 Maximum Near-surface Wind Speed (10m) Maximum near-surface wind speed (10 m)km/hWIND_MAX_YS30 Snow DepthAverage snow depthcmSND_YS31 Maximum Snow DepthMaximum snow depthcmSND_MAX_YSJeux de données disponibles au téléchargement
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Linked dataset resource
Informations supplémentaires
| Champ | Valeur |
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| Dernière mise à jour | juillet 3, 2026, 07:14 (TU) |
| Créé | juillet 1, 2026, 07:13 (TU) |
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Titre
Titre du jeu de données.
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TRCA Climate Data - Change in Lake Ontario Temperature, Precipitation, and Other Climate Variables |
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Description
Une description du jeu de données.
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This file is a download link climate variables between 1981-2010 and 1991-2020 reflecting changes in temperature, precipitation, wind, and snow depth changes. The data can be explored through the WLO Data Explorer, along with other environmental layers. Project Description The “Compendium of Coastal Resilience Issues and Typology of Nature-based and Hybrid Solutions” project was supported by the Province of Ontario and the Canada Water Agency. Stretching between the Niagara River in the south to Cobourg in the east, Western Lake Ontario is home to nearly a quarter of Canada’s population and the fastest growing region in the Great Lakes Basin. Climate change poses a growing threat to communities and ecosystems along Western Lake Ontario, intensifying existing pressures such as urbanization, land conversion, and legacy contamination. To help address these challenges, the Land to Lake Initiative was established in 2022 to foster stronger, more coordinated collaborations to enhance capacity for actions that improve water quality and ecosystem health in Western Lake Ontario. This study supports the objectives of this partnership initiative by:
For more information about this project, please see our project webpage: https://trca.ca/land-to-lake/issues-solutions-compendium/ Data Description The Canadian Surface Reanalysis (CaSR, version 3.2, 1980-2024), developed by Environment and Climate Change Canada provides detailed gridded atmospheric and land-surface forcings on a 10 km x 10 km grid, spanning approximately 43 years (1980–2023) with sub-daily and daily temporal resolution. By blending ERA5 global atmospheric data with local observations through the Regional Deterministic Reforecast System (RDRS) and the Canadian Land Data Assimilation System (CaLDAS), it generates critical variables such as 1-hour rainfall and snowfall totals and 3-hour air temperature. This dataset is primarily designed to provide high-quality, consistent inputs for advanced hydrological and surface models. In this study, the daily dataset covering the 1980-2023 time period was extracted to calculate climate variables, reflecting changes in temperature, precipitation, wind, and snow depth changes. The data was accessed and analyzed from https://hpfx.collab.science.gc.ca/~scar700/rcas-casr/ in April 2026. Changes in climate variables between 1981–2010 and 1991–2020 are provided as open data. Layers for both time periods are available upon request (see Table 1 for the full list of climate variables available). Please email [email protected]. Table 1. List of climate variables Climate VariableDescriptionUnitSymbol1 Annual Mean TemperatureMean temperature (°C) is defined as the average of the maximum and minimum temperature at a location for a specified time interval°CTG_YS2 Winter Mean TemperatureWinter months include: December, January, and February (DFJ)°CTG_DJF3 Spring Mean TemperatureSpring months include: March, April, and May (MAM)°CTG_MAM4 Summer Mean TemperatureSummer months include: June, July, and August (JJA)°CTG_JJA5 Fall Mean TemperatureFall months include: September, October, and November (SON)°CTG_SON6 Annual Maximum TemperatureThe average of daily maximum temperatures (°C) at a location for a specified time interval°CTX_YS7 Winter Maximum TemperatureWinter months include: December, January, and February (DFJ)°CTX_DJF8 Spring Maximum TemperatureSpring months include: March, April, and May (MAM)°CTX_MAM9 Summer Maximum TemperatureSummer months include: June, July, and August (JJA)°CTX_JJA10 Fall Maximum TemperatureFall months include: September, October, and November (SON)°CTX_SON11 Annual Minimum TemperatureThe average of daily minimum temperatures (°C) at a location for a specified time interval°CTN_YS12 Winter Minimum TemperatureWinter months include: December, January, and February (DFJ)°CTN_DJF13 Spring Minimum TemperatureSpring months include: March, April, and May (MAM)°CTN_MAM14 Summer Minimum TemperatureSummer months include: June, July, and August (JJA)°CTN_JJA15 Fall Minimum TemperatureFall months include: September, October, and November (SON)°CTN_SON16 Annual Total PrecipitationThe sum of the total rainfall and the water equivalent of the total snowfall (mm) at the location during a specified time intervalmmPR_YS17 Winter Total PrecipitationWinter months include: December, January, and February (DFJ)mmPR_DJF18 Spring Total PrecipitationSpring months include: March, April, and May (MAM)mmPR_MAM19 Summer Total PrecipitationSummer months include: June, July, and August (JJA)mmPR_JJA20 Fall Total PrecipitationFall months include: September, October, and November (SON)mmPR_SON21 Days Below 0°C (Frost Days)The number of days in a year when daily minimum temperature is lower than 0˚C (or < 0˚C). Under these conditions, frost may form on the ground or on cold surfacesdays/yearTN022 Number of Days with Maximum Temperature > 30˚CThe number of days in a year when daily maximum temperature exceeds 30˚C (or > 30˚C)DaysTX3023 Number of Days with Minimum Temperature < -15˚CThe number of days in a year when daily minimum temperature drops below -15˚C (or < -15˚C)DaysTN-1524 Diurnal Temperature RangeDifference between daily maximum and daily minimum air temperature at a location for a specified time interval°CDTR25 Hottest Day Temperature/ Maximum Maximum TemperatureHighest maximum ("day-time") daily air temperature (°C) at a location for a specified time interval°CTXx26 Coldest Day Temperature/ Minimum Minimum TemperatureLowest minimum ("night-time") daily air temperature (°C) at a location for a specified time interval°CTNn27 Simple Daily Intensity IndexAverage intensity (mm/day) over a given period of time, calculated as total wet day precipitation (> 1 mm) divided by the total number of wet daysmm/daySDII28 Near-surface Wind Speed (10m)Average near-surface wind speed (10 m)km/hWIND_YS29 Maximum Near-surface Wind Speed (10m) Maximum near-surface wind speed (10 m)km/hWIND_MAX_YS30 Snow DepthAverage snow depthcmSND_YS31 Maximum Snow DepthMaximum snow depthcmSND_MAX_YS |
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0.07 |
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2026-06-30 |
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public (affichage de la valeur pour English) |
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Toronto and Region Conservation Authority (TRCA) Open Data Licence v1.0 - Toronto and Region Conservation Authority (TRCA) |
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https://trca-camaps.opendata.arcgis.com/datasets/camaps::trca-climate-data-change-in-lake-ontario-temperature-precipitation-and-other-climate-variables (affichage de la valeur pour English) |
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trca_d.macleod (affichage de la valeur pour English) |
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Conservation Ontario (affichage de la valeur pour English) |
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[email protected] (affichage de la valeur pour English) |
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Conservation Ontario (affichage de la valeur pour English) |
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trca_d.macleod |
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2026-07-02 |
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1e6d263028e7467887fa9adbde4ce9e0 (affichage de la valeur pour English) |
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English |
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https://trca-camaps.opendata.arcgis.com/datasets/camaps::trca-climate-data-change-in-lake-ontario-temperature-precipitation-and-other-climate-variables (affichage de la valeur pour English) |
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Conservation Ontario (affichage de la valeur pour English) |
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