Choosing an Awning by Patio Orientation: South, East, West and North-Facing Patios

The direction your patio faces decides what kind of awning works. A south-facing patio gets high sun from in front, so a standard retractable awning shades most of its footprint from mid-morning to mid-afternoon in summer. A west-facing patio gets its hardest sun late in the day, low and straight in front, so an awning alone stops working when you most want it: plan on a drop shade, side panel or screen. An east-facing patio is the mirror image, and pleasant by afternoon without any help. A north-facing patio sits in the house's shadow most of the day and usually needs rain cover more than shade.

The numbers below come from standard solar geometry for a reference awning (10 ft projection, front bar 7.5 ft above the ground, flat patio), the same model used on the awning shade data page. For the formula and its parts, start with how much shade an awning provides.

Find your orientation first

Orientation means the direction you face when you stand with your back to the wall and look out over the patio. Use a phone compass, but correct for the difference between magnetic and true north: magnetic declination reaches roughly 10 to 15 degrees in the West (east of true north) and the Northeast (west of true north), enough to turn a "southwest" patio into a "south-southwest" one. Many compass apps can show true north directly. A satellite map view, which is aligned to true north, is a quick cross-check.

Very few walls face exactly a cardinal direction. Treat anything within about 20 degrees of a cardinal point as that direction, and use the angled-wall guidance below for the rest.

Shade by orientation, hour by hour

This table shows the depth of shade, measured out from the wall, for the reference awning at 40 degrees north (Denver, Philadelphia, Columbus) on August 1. Times are solar time; add roughly 1 hour or a bit more for daylight saving clock time.

"Building shade" means the sun is behind or level with the wall, so the house itself shades the patio. "0 ft" means the front bar's shadow falls against the wall and the whole patio in front of the house is in sun. Across US latitudes these hourly patterns change little in midsummer; latitude matters much more in spring and fall (see sun angles for awning design).

South-facing patios

South is the best case. In summer the sun crosses high in front of the wall, and as it swings east or west in the morning and afternoon, the profile angle (the sun's height measured in a slice straight out from the wall) actually gets steeper, so shade depth holds up from about 8 am to 4 pm solar time. The main issues:

• Late season. By the September equinox the noon sun at 40 degrees north is about 50 degrees high and the reference awning shades only about 3.7 ft. Northern households that use the patio into September benefit from 12 ft or more of projection, extra pitch, or a valance.
• Sideways drift. In mid-afternoon the shaded patch slides east along the wall by several feet. Size the awning 2 to 4 ft wider than the seating area, or add a side panel on the west end.
• Winter sun. A south patio and the rooms behind it gain welcome sun in winter. A retractable awning lets you keep it; a fixed cover gives it up.

Best fit: a lateral-arm retractable sized 1 to 2 ft deeper than the seating area, with a moderate pitch.

West-facing patios

West is the hardest orientation and the one most often under-specified. The patio sits in the house's shadow until about noon, then takes the full afternoon sun. Through the afternoon the sun drops toward the horizon almost straight in front of the wall, so the shadow of the front bar retreats toward the house: about 5.7 ft of shade at 2 pm, about 3 ft at 3 pm, and none by 4 pm solar time, which is after 5 pm on a daylight saving clock. That is dinner time, the hottest part of the day for the patio and the adjoining rooms.

More projection does little against a low sun. A lower front edge does a lot, because the shade-depth formula subtracts front edge height divided by the tangent of the profile angle, and that tangent is small when the sun is low.

Because the sun on a west wall is also lower in the sky as you sit, glare matters as much as heat. A mesh drop shade or solar screen blocks most of the direct sun while keeping a view. West windows behind the patio also gain the most from shading: the U.S. Department of Energy, Energy Saver, puts the reduction in summer solar heat gain at up to 77% for awnings on west-facing windows.

Best fit: a retractable with an integrated or add-on drop valance, or a separate motorized screen; a side panel on the south end for early afternoon.

East-facing patios

East is the mirror image of west. The patio gets low sun from straight in front in the early morning: no useful awning shade before about 9 am solar time, about 5.7 ft by 10 am, and house shade from late morning on. In most US climates morning sun is cooler and many people enjoy it, so east patios often need less than any other orientation except north.

• If you use the patio for breakfast and want shade then, treat it like a west patio: a drop shade is the effective tool.
• If you mainly use it in the afternoon and evening, the house shades it and an awning is mostly for rain and for shading east windows in the morning.
• In hot, humid climates, morning sun on east windows still adds cooling load; a modest window awning or a short retractable helps.

Best fit: a smaller retractable, or a drop shade alone if morning use is the priority.

North-facing patios

A north patio is in the building's shadow for most of the day all year. In early summer, though, the sun rises and sets well north of due east and west (at 40 degrees north, about 31 degrees north of east at the June solstice), so a north wall gets low sun for an hour or two after sunrise and before sunset. That sun is weak for heat but can be glaring at evening meals.

The real case for an awning on a north patio is weather: rain cover, protection for furniture, and a dry route to the door. That changes the product choice:

• A fixed awning or a rigid aluminum or polycarbonate cover (see awning vs patio cover) handles rain better than a retractable, which should be pitched at least about 14 degrees for drainage and retracted in heavy rain.
• Choose lighter colors or translucent panels: north rooms are already dim, and a dark awning makes them darker.
• Mildew is more likely on fabric that rarely sees sun; plan on cleaning more often (see awning mold and mildew).

Southeast and southwest walls

Angled walls behave like a blend. A southwest patio holds good shade around midday (about 7.8 ft at noon, 5.1 ft at 2 pm in the table above) but loses it through the late afternoon, reaching about 1.6 ft by 4 pm and zero by 5 pm solar time. It needs the same late-day help as a west patio, but for a shorter window. A southeast patio is the reverse and is one of the most comfortable orientations in hot climates: morning sun is moderated by the awning and the house takes over after noon.

Recommended solutions by orientation

Translate solar time to your clock

All hours above are solar time. On daylight saving time, add an hour, then adjust for your position in the time zone: about 4 minutes later for every degree of longitude you are west of the zone's reference meridian (75, 90, 105 or 120 degrees west), earlier if you are east of it. Chicago (87.6 degrees west, Central time) has summer solar noon around 12:50 to 1:00 pm; Detroit (83 degrees west, Eastern time) around 1:30 to 1:45 pm. So "4 pm solar" on a west patio in Detroit is close to 5:40 pm on the clock.

Who needs to think hardest about orientation

• Anyone with a west or southwest patio who eats outside in the evening: budget for a drop shade from the start.
• North of about 40 degrees, anyone who wants shade into September: check equinox shade, not midsummer.
• Owners of north or east patios: you may need far less awning than a brochure suggests, or a rain cover instead.
• Anyone shading windows behind the patio: see window awnings for orientation-specific sizing.

To check your own patio, the shade calculator takes latitude, date, time, wall direction, projection and mounting height, and the awning size planner turns the result into a width and projection.

Frequently asked questions

What is the best orientation for an awning?

A south-facing wall is the easiest to shade with an awning alone, because the summer sun stays high and in front of the wall for most of the day. A standard 10 ft retractable shades roughly 7 to 9 ft from the wall from mid-morning to mid-afternoon in midsummer across most of the US. West-facing walls need the most help.

Why doesn't my west-facing awning shade the patio in the evening?

In late afternoon the sun is low and almost straight in front of a west wall, so its rays pass under the front bar and the bar's shadow falls back against the house. At 40 degrees north in August the reference awning shades nothing by about 4 pm solar time. A drop shade or screen hanging from the front bar is the effective fix.

Do I need an awning on a north-facing patio?

Usually not for shade, since the house shades a north patio most of the day. It gets only low sun shortly after sunrise and before sunset in early summer. An awning or cover on a north patio is mainly for rain protection and furniture, where a fixed or rigid cover often beats a retractable.

Is a bigger awning better for a west-facing patio?

Not by much. Against a low sun, 2 ft of extra projection may add only about 1 ft of shade, while a drop shade that lowers the effective front edge from 7.5 ft to 3.5 ft can add about 5 ft at the same hour. Spend first on a drop valance or screen, then on projection.

How do I tell which way my patio faces?

Stand with your back to the wall, facing out over the patio, and read a compass set to true north, or check the house on a satellite map view, which is aligned to true north. Magnetic compasses can be off by 10 to 15 degrees in the West and Northeast, which matters for angled walls.

Sources and further reading

• U.S. Department of Energy, Energy Saver: Energy Efficient Window Attachments
• NOAA Global Monitoring Laboratory: NOAA Solar Calculator
• NOAA National Centers for Environmental Information: Magnetic Field Calculators (magnetic declination)
• Duffie, J. A. and Beckman, W. A.: Solar Engineering of Thermal Processes (Wiley), solar geometry chapter