PV Snow Loss Calculator — Taylor Scott Solar PV Toolset

Project Information

Project Name (optional)

Notes (optional)

Site Coordinates (Decimal Degrees)

Latitude (°N)

°N

Longitude (°E — West is negative)

°E

ℹ Ottawa ON = 45.42, −75.69 · Montreal QC = 45.51, −73.56 · Toronto ON = 43.65, −79.38 · Calgary AB = 51.05, −114.07

Study Period — ERA5 Hourly Data (for Marion Model)

Start Year

End Year

ℹ Used for ERA5 hourly simulation (Marion model) and as fallback for any variables not available from the EC station. 5–10 years is recommended. EC Climate Normals cover 1981–2010 regardless of this period.

Environment Canada Climate Station

EC 1981–2010 normals are used for snowfall, snow days, temperature, and humidity where available — these are more defensible than a sample-period ERA5 average. Not all stations carry snow data; the tool checks each candidate and reports what's available. Solar irradiance is always sourced from ERA5 (EC does not collect this at most stations).

Monthly Climate Data — Averaged Over Study Period / Normals Period

Edit any cell to override with project-specific or station-measured values. Source of each value is shown by the left-border colour.
Excel/Sheets paste: click the first cell you want to fill, then paste (Ctrl+V / ⌘V). Paste a single row of 12 monthly values to fill one column, or a full grid (months × columns) to fill multiple variables at once. Column order: Snowfall · Snow Days · Avg Temp · Avg RH · POA Irradiance.

EC Climate Normal (1981–2010) ERA5 reanalysis average User override

Month	Total Snowfall (cm/month)	Snow Event Days/month	Avg Temp (°C)	Avg Rel. Humidity (%)	POA Irradiance (kWh/m²/month)
No data loaded — complete Project Setup and fetch climate data.

Array Geometry

Tilt Angle

Azimuth (0° = North, 180° = South)

Mounting Type

Row Length (along slope)

Lower Edge Height (above grade)

System DC Power (optional)

kWp

ℹ Row Length: Panel dimension along the slope. Lower Edge Height: Height of panel's lower edge above grade — drives Townsend ground-interference term. Note: Tilt and Azimuth are also used when fetching POA irradiance from ERA5 — set these before fetching if possible.

Model Constants — Advanced Overrides

Marion Sliding Coeff. — Ground (default 6.0)

Marion Sliding Coeff. — Roof (default 1.97)

Townsend C₁ (default 57 000)

Townsend C₂ (default 0.5)

Townsend Pile Angle (default 40°)

Marion Thermal Param. m (default 80)

Townsend String Multiplier M

⚠ Defaults are from the reference literature. Modified constants are flagged in Engineering Details and exports. Marion sliding coefficient has the highest sensitivity impact.

ℹ No results yet — fetch climate data (tab 1), configure array (tab 3), then click Calculate Snow Losses.

ℹ Run a calculation first to see intermediate terms and the assumptions audit trail.