What is the best angle for solar panels in Toronto?

About 29 degrees, which is Toronto's latitude minus fifteen, not its latitude. Natural Resources Canada publishes photovoltaic potential at four fixed tilts for every municipality, and for Toronto the figures are 1,174 kWh a year per kW at latitude minus fifteen, 1,163 at latitude tilt, 1,096 at latitude plus fifteen and 1,013 horizontal. The widely repeated advice to set the tilt to your latitude is therefore slightly off for southern Ontario, though only by about 11 kWh per kW a year, which is under one percent.

Does my roof pitch matter for solar?

Far less than almost anything else about the installation, and that is the useful conclusion here. On NRCan's Toronto figures a 4:12 roof at 18.4 degrees gives up about 5 percent against the best tilt, a 6:12 roof at 26.6 degrees gives up about 1 percent, and an 8:12 roof at 33.7 degrees gives up under half a percent. Anywhere between roughly 4:12 and 8:12, which covers most Ontario housing, you are within a rounding error of optimal. Nobody should pay to tilt an array off a roof in that range.

Is the rule 'set the tilt to your latitude' wrong?

It is a good approximation that is slightly conservative for southern Ontario. The rule comes from optimising for the sun's average elevation across the year, but real solar resource is weighted toward the summer months, when the sun is high and the days are long. A shallower panel catches more of that. NRCan's own numbers show the effect directly: latitude minus fifteen beats latitude tilt in Toronto for annual output. The margin is small enough that the rule remains fine advice, but the data is worth having rather than the slogan.

Should I change the tilt with the seasons?

Only if the array is on an adjustable ground mount, in which case yes and the gain is real. NRCan's Toronto monthly figures show a steep tilt of about 59 degrees winning every month from November through February, a shallow tilt of about 29 degrees winning from April through September, and latitude tilt winning in March and October. In December the steep tilt makes 55 kWh per kW against 45 for the shallow one, which is over 20 percent. On a fixed roof array none of this is actionable, which is why the table says which reader it is for.

A steeper panel sheds it and a shallow one holds it, and NRCan states explicitly that its monthly values do not model snow cover. So in a Toronto winter a steep tilt has a second advantage on top of the one in the numbers: the array is more likely to be clear and generating at all. This cuts against the shallow tilt that wins on annual output, and it is one reason the difference between tilts in practice is smaller and messier than a table of annual figures suggests.

Does direction matter more than angle?

Considerably more, and if you have to choose which to get right, choose direction. Across all the fixed tilts NRCan publishes for Toronto facing south, the spread between the best and the worst sensible roof pitch is a few percent. Turning the array away from south costs far more than that. Everything on this page assumes a south-facing array, and orientation is treated separately in our roof suitability checker.

What angle should solar panels be set at?

Every page answering this repeats the same rule: set the tilt to your latitude. For Toronto, Natural Resources Canada's own published figures say otherwise, and the more useful finding underneath is that on any ordinary roof pitch the difference barely matters at all.

Last updated August 25, 2026By The SolarPanelFinder Rooftop Desk

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The practical answer for most people reading this: do not pay to change your roof pitch. If your roof faces roughly south and sits anywhere between 4:12 and 8:12, the tilt is already close enough that fixing it would cost far more than the electricity it bought.

What does your tilt actually cost you?

Tilt angleFlat is 0, a vertical wall is 90.Or pick your roof pitchArray size

26.6 degrees, about a 6:12 roof

1,162 kWh a year per kW - 1.0% off the best

The best fixed tilt Natural Resources Canada publishes for Toronto is 28.7 degrees at 1,174 kWh per kW - which is latitude minus fifteen, not latitude. Over an 8 kW array that difference is 94 kWh a year.

Horizontal - 0.0 degrees: 1,013 kWh/kW
Latitude minus 15 - 28.7 degrees: 1,174 kWh/kW
Latitude tilt - 43.7 degrees: 1,163 kWh/kW
Latitude plus 15 - 58.7 degrees: 1,096 kWh/kW
Vertical - 90.0 degrees: 802 kWh/kW

NRCan publishes four fixed tilts, not a continuous curve, so the figure for 26.6 degrees is interpolated in a straight line between the two published points either side of it. The real curve is smooth rather than piecewise, so treat this as close rather than exact. The five published points themselves are listed above, unaltered.

Which tilt wins each month, if you can actually change it

Shallow is 28.7 degrees, latitude is 43.7, steep is 58.7. Toronto figures, kWh per kW that month.

Month	Shallow	Latitude	Steep	Wins
Jan	58	66	70	Steep
Feb	75	82	85	Steep
Mar	105	109	107	Latitude
Apr	117	113	104	Shallow
May	131	122	107	Shallow
Jun	136	123	105	Shallow
Jul	141	128	111	Shallow
Aug	128	121	109	Shallow
Sep	103	103	98	Shallow
Oct	84	89	89	Latitude
Nov	50	55	57	Steep
Dec	45	51	55	Steep

All of this assumes the array faces south. Turning away from south costs more than getting the tilt wrong does, and it is a separate question. NRCan also cautions that its monthly values are indicative only and do not model snow cover, which in a Toronto January is exactly when a steeper panel has a second advantage the numbers above do not capture: it sheds snow that a shallow one holds.

The method

Why latitude minus fifteen, and not latitude

The rule optimises for the sun's average height. The resource is weighted toward summer.

The latitude rule comes from a sensible piece of geometry: over a whole year the sun's average elevation at solar noon is roughly ninety degrees minus your latitude, so a panel tilted at your latitude faces the average sun squarely. It is a good approximation and it is why the rule has survived so long.

What it misses is that the year is not evenly weighted. Toronto in June gets long days and a high sun; Toronto in December gets short days, a low sun and a lot of cloud. Far more of the annual solar resource arrives in the summer half of the year, so a panel that favours the high summer sun collects more over twelve months than one optimised for the average. NRCan's figures show exactly that: 1,174 kWh per kW at about 29 degrees against 1,163 at about 44.

The honest framing of that finding is that it is small. Eleven kilowatt-hours per kilowatt per year is under one percent, which on a typical array is a few dollars. What is genuinely worth acting on is the shape of the curve either side of the optimum, and it is flat. Between roughly 20 and 40 degrees the annual output barely moves. That is the range almost every Ontario roof already sits in, which is why the answer for most readers is to leave it alone.

Seasonal adjustment is the part of this dataset with a real effect, and it is only available to a minority of readers. NRCan publishes Toronto month by month at each tilt, and the winter numbers are dramatic: in December a steep panel makes twenty-odd percent more than a shallow one, because the sun barely rises and a near-vertical surface faces it much more directly. Anyone with an adjustable ground mount can collect that by moving the array twice a year. Anyone with panels bolted to a roof cannot, and the table on this page marks which is which rather than presenting a fact nobody can use as advice.

One caution on the arithmetic itself. NRCan publishes four fixed tilts, not a continuous curve. When you enter an angle that is not one of them, this page interpolates in a straight line between the two published points either side, and it tells you on screen when it has done so. The true relationship is a smooth curve, so an interpolated figure is close rather than exact. The published points are always shown unaltered beside it.

Frequently asked questions

What is the best angle for solar panels in Toronto?: About 29 degrees, which is Toronto's latitude minus fifteen, not its latitude. Natural Resources Canada publishes photovoltaic potential at four fixed tilts for every municipality, and for Toronto the figures are 1,174 kWh a year per kW at latitude minus fifteen, 1,163 at latitude tilt, 1,096 at latitude plus fifteen and 1,013 horizontal. The widely repeated advice to set the tilt to your latitude is therefore slightly off for southern Ontario, though only by about 11 kWh per kW a year, which is under one percent.
Does my roof pitch matter for solar?: Far less than almost anything else about the installation, and that is the useful conclusion here. On NRCan's Toronto figures a 4:12 roof at 18.4 degrees gives up about 5 percent against the best tilt, a 6:12 roof at 26.6 degrees gives up about 1 percent, and an 8:12 roof at 33.7 degrees gives up under half a percent. Anywhere between roughly 4:12 and 8:12, which covers most Ontario housing, you are within a rounding error of optimal. Nobody should pay to tilt an array off a roof in that range.
Is the rule 'set the tilt to your latitude' wrong?: It is a good approximation that is slightly conservative for southern Ontario. The rule comes from optimising for the sun's average elevation across the year, but real solar resource is weighted toward the summer months, when the sun is high and the days are long. A shallower panel catches more of that. NRCan's own numbers show the effect directly: latitude minus fifteen beats latitude tilt in Toronto for annual output. The margin is small enough that the rule remains fine advice, but the data is worth having rather than the slogan.
Should I change the tilt with the seasons?: Only if the array is on an adjustable ground mount, in which case yes and the gain is real. NRCan's Toronto monthly figures show a steep tilt of about 59 degrees winning every month from November through February, a shallow tilt of about 29 degrees winning from April through September, and latitude tilt winning in March and October. In December the steep tilt makes 55 kWh per kW against 45 for the shallow one, which is over 20 percent. On a fixed roof array none of this is actionable, which is why the table says which reader it is for.
What about snow?: A steeper panel sheds it and a shallow one holds it, and NRCan states explicitly that its monthly values do not model snow cover. So in a Toronto winter a steep tilt has a second advantage on top of the one in the numbers: the array is more likely to be clear and generating at all. This cuts against the shallow tilt that wins on annual output, and it is one reason the difference between tilts in practice is smaller and messier than a table of annual figures suggests.
Does direction matter more than angle?: Considerably more, and if you have to choose which to get right, choose direction. Across all the fixed tilts NRCan publishes for Toronto facing south, the spread between the best and the worst sensible roof pitch is a few percent. Turning the array away from south costs far more than that. Everything on this page assumes a south-facing array, and orientation is treated separately in our roof suitability checker.

Sources

Where these figures come from

Natural Resources Canada, Photovoltaic potential and solar resource maps of Canada - every tilt figure on this page, annual and monthly, for Toronto. NRCan publishes six array orientations per municipality and applies a performance ratio of 0.75. It states that most systems land within about 10 percent of the annual figures, and that the monthly ones are indicative only and do not model snow cover or an unusually cloudy year.
Roof pitch angles are trigonometry, not a published figure: a rise of n in 12 is an angle of arctan(n/12). No source is needed for that and none is claimed.