Seasonal Solar Production Calculator Canada
Calculate your solar panel output month-by-month for any Canadian province — including snow losses, winter shortfall, required battery autonomy, and how much to oversize your system for year-round reliability.
✓ Based on NRCan solar irradiance data · Updated March 2026⚙️ System & Location Settings
📊 Results
Monthly Solar Production vs. Consumption
Month-by-Month Breakdown
| Month | Peak Sun Hours | Snow Loss | Production (kWh) | Consumption (kWh) | Balance (kWh) | Status |
|---|
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This calculator uses monthly peak sun hour (PSH) averages for each Canadian province, sourced from Natural Resources Canada's solar irradiance data. Here's what each input does:
- Array Size: Total installed DC capacity of your solar panels in kilowatts
- System Efficiency: Combined losses from inverter, wiring, temperature, and soiling — typically 85–90%
- Daily Consumption: Your average daily energy use; affects the surplus/deficit calculation
- Snow Loss Factor: Percentage of winter production lost to snow coverage — higher for flat roofs, lower for steep south-facing arrays
- Panel Degradation: Annual reduction in panel output — affects multi-year projections
- Battery Capacity: For off-grid systems, used to calculate how many days of autonomy your bank provides in each month
Understanding Your Seasonal Results
Why Canadian Solar Has Such Dramatic Seasonal Swings
Canada's high latitude means enormous variation in daily solar irradiance between summer and winter. A solar system in southern Ontario receives roughly 5.8 peak sun hours per day in June but only 1.9 hours per day in December — a 3× difference. In Edmonton, that gap is even wider. This is why sizing a Canadian off-grid system on annual averages leads to systems that fail in winter.
What the Winter Shortfall Means for Off-Grid Systems
The winter shortfall figure shows how many kilowatt-hours per month your solar panels can't cover based on your daily consumption and system size. For off-grid systems, this shortfall must be covered by either your battery bank (if large enough) or a backup generator. The "days of autonomy" figure shows how many days your battery bank alone can bridge the gap in each month — critical for planning generator run time.
Panel Oversizing Recommendation
The calculator recommends a minimum array size to cover your worst-month consumption without relying entirely on battery storage or generator backup. This "winter-optimized" array size is typically 50–100% larger than what a simple annual average calculation would suggest for northern Canadian locations.
Provincial Solar Data Sources
Monthly peak sun hours in this calculator are derived from Natural Resources Canada's solar irradiance datasets and PVGIS European Commission data, cross-referenced with representative cities in each province. Values represent horizontal irradiance adjusted for a south-facing array at optimal tilt angle.
Frequently Asked Questions
How much does solar production drop in Canadian winters?
It varies significantly by province. In southern Ontario and BC, winter production is typically 30–40% of summer peak. In the Prairie provinces, winter production drops to 25–35% of summer levels despite good solar resources, due to very short days. Northern territories can see near-zero production for several weeks in December–January. This calculator shows your exact monthly figures for your province.
What is peak sun hours (PSH) and how is it different from daylight hours?
Peak sun hours measure the total solar energy received in a day, expressed as equivalent hours of full-strength sunshine (1,000 W/m²). A day with 4 peak sun hours means your panels received the equivalent energy of 4 hours of maximum-intensity sun, even if it was actually sunny for 8 hours at varying intensities. PSH is the standard metric used for solar system sizing.
Should I size my solar system for summer or winter production?
For off-grid systems in Canada, always size for your worst month (typically December or January). A system sized for winter will overproduce significantly in summer — which is fine for grid-tied systems with net metering credits, and manageable for off-grid systems where excess can charge batteries fully. Sizing for summer and hoping winter works out is the most common and costly mistake in Canadian off-grid design.
How does snow affect solar production in Canada?
Snow on panels can reduce output by 50–100% until it clears. Steep panels (45°+) shed snow naturally within a day or two of snowfall. Flat or low-tilt panels can remain covered for weeks. The snow loss factor in this calculator applies a realistic seasonal average — actual loss on any specific day will vary. Manual clearing with a soft brush or roof rake is recommended for flat installations after heavy snowfall.
How many days of battery autonomy do I need for a Canadian off-grid system?
Southern Canada (ON, QC, BC): 3–5 days. Prairie provinces: 4–5 days. Atlantic Canada: 4–6 days. Northern territories: 7–10 days with strong generator backup. The autonomy figure in this calculator shows what your current battery bank provides in each month — compare this to the recommended minimums for your region.
What does "panel oversizing recommendation" mean?
It's the minimum array size needed to cover your monthly consumption in your worst solar month, without relying entirely on battery storage. If your current array is smaller than this figure, your off-grid system will need significant generator runtime in winter, or you'll need to reduce consumption. Adding more panels is usually cheaper than running a generator long-term.
Related Solar Calculators
Data Sources & References
All solar irradiance values, snow loss factors, and provincial electricity rates used in this calculator are drawn from official government and authoritative research sources.
☀️ Solar Irradiance & Production Data
- Photovoltaic Potential and Solar Resource Maps — Natural Resources Canada (NRCan) — Provincial monthly solar irradiance and peak sun hour data
- PVGIS (Photovoltaic Geographical Information System) — European Commission Joint Research Centre — Monthly irradiance cross-reference by province representative city
- Solar Energy in Canada — Natural Resources Canada — National solar resource overview and regional variation data
❄️ Snow Loss & Cold Climate Factors
- Rural and Remote Communities Energy — Natural Resources Canada — Cold climate solar installation guidelines and snow impact references
- Canadian Electrical Code (CEC) — Standards Council of Canada — Snow load and installation standards for Canadian solar systems
💡 Provincial Electricity Rates
- Provincial Solar Savings & Net Metering Rates — Canadian Renewable Energy Association (CanREA), updated February 2025
- Provincial utility regulatory filings — BC Hydro, Hydro One (ON), Hydro-Québec, NS Power, NB Power, Manitoba Hydro, SaskPower, ATCO (AB/YT), NTPC (NT), Qulliq Energy (NU)
📊 System Efficiency & Degradation
- PV System Performance — National Renewable Energy Laboratory (NREL) — System efficiency loss factors and panel degradation rate benchmarks
- Canadian Renewable Energy Statistics — CanREA — Canadian solar capacity and performance benchmarks
Monthly peak sun hour values are provincial averages based on NRCan solar irradiance data and PVGIS datasets as of Q1 2026. Actual production varies by exact location, panel orientation, shading, soiling, and local weather. Snow loss factors are estimates — actual losses depend on roof pitch, panel tilt, local snowfall patterns, and clearing frequency. Electricity rates reflect provincial averages from CanREA (February 2025 update) and utility regulatory filings. This calculator is intended for planning and educational purposes only. Always obtain a professional site assessment before purchasing equipment. Solar irradiance data sourced from PVGIS / NRCan — provincial averages based on representative cities.