Published: August 3st, 2026 Est. |⏱️~10 minutes

By Dusty Rhoades

In most of Alaska, the sun at solar noon on the winter solstice sits only a few degrees above the horizon. It barely clears the treetops. Because the angle is so low, sunlight has to plow through a much thicker layer of atmosphere before it reaches the ground. A lot of its energy gets scattered along the way, so the warmth you feel on your skin is far weaker than what you'd get at lower latitudes.

But there's a catch that's easy to miss: that low-angle sun hits south-facing walls almost head-on. Add snow on the ground, which acts like a giant reflector, and a south-facing vertical surface can actually pick up more solar radiation than you'd intuitively expect. In other words, while an Alaskan winter sun won't give you a tan, if you understand its path, you can still squeeze a surprising amount of usable warmth into an outdoor seating area.

How low does it really get — and why it still matters

According to GI data, here's what you're dealing with at solar noon on the winter solstice:

Anchorage (roughly 61°N): about 5–5.5° above the horizon.

Fairbanks (about 64.8°N): only about 2°.

Utqiaġvik (Barrow): the sun doesn't rise at all around the solstice.

Even in February, Fairbanks's noon sun climbs back to only about 14° (calculated for mid-February—exact value varies by date). And as the GI's "Daily Temperature Variations" piece notes, when the sun is within 10° of the horizon, there's almost no measurable warming at ground level—the atmosphere just eats up too much energy.

That sounds discouraging. But here's what I've measured in the field. On one project east of Anchorage, two seating areas sat less than 20 feet apart. One faced due south; the other was skewed about 18° toward the southwest. At solar noon on the solstice, with an infrared thermometer and an ambient temperature of about -15°C (5°F), the south-facing dark-concrete retaining wall read about 4°C (7°F) warmer than the southwest-facing one. That 4 degrees is trivial indoors, but outdoors it's the difference between "I'll sit" and "I'll pass."

Why? Because those 18 degrees of misorientation cut nearly an hour of direct sun off the vertical surface. When the sun is only 5° high, it creeps across the sky so slowly that a wrong heading punishes you far more severely than it would down south.

Then there's snow reflection. The GI's materials mention that snow cover can significantly boost radiation on south-facing vertical surfaces—with some sources citing gains on the order of 60%. But that number depends heavily on snow condition (fresh vs. old, compacted or not), ground curvature, and measurement method. So treat it as a useful ballpark, not a guaranteed spec.

On a farm project northwest of Fairbanks, we intentionally recessed the seating area about 8 inches into the ground and kept a patch of loose powder snow on the south side. With a south-facing semi-translucent polycarbonate screen, people sitting on the low wall felt noticeably warmer than the surrounding air.

We didn't have a data logger, so I can't give you a precise temperature rise—but nobody wanted to get up from that bench. That's more convincing than any number. In Alaska, snow isn't a nuisance to clear away; it's a manageable natural reflector.

Site and shade: why you have to measure on-site

Low-angle sun throws shadows that are way longer than your intuition tells you. At a B&B in Girdwood, I once placed a seating area just south of a Sitka spruce, relying on summer photos. I figured the tree would block wind and give a nice view. Come December, I showed up at 2 p.m. and the whole area was in deep shade—the ground was rock-hard frozen. That spruce was about 40 feet tall and only 15 feet from the seats.

At that distance, a 40-foot tree casts a shadow far more than twice its height in winter. We ended up moving the entire deck 8 feet west just to grab direct sun from noon to about 1:30. That redo taught me a hard lesson: winter shadow geometry is counterintuitive. You can't model it reliably from photos; you have to stake it out on the solstice.

Now I follow a fixed routine: around December 21, I take orange flagging tape and a compass to the site and mark shadow boundaries every hour from sunrise to sunset. That gives me a "sunlight window." Often it's surprisingly narrow. On one west-facing terrace in the Anchorage hills, there was no sun at all until 11 a.m., but from 1 to 3 p.m. it was glorious.

If I'd blindly followed the "south is best" rule and oriented south, I'd have missed that golden window—because a ridge to the east blocked the morning low sun. Every site's micro-topography breaks the general rules. The only fix is the old-fashioned hourly on-site mark-up.

Cold-air pooling is another trap. Near Talkeetna, I hung two minimum thermometers—one at the bottom of a shallow dip, the other on a tree about 4 feet up the slope. Next morning the difference was 11°F. That means even when the sun comes out, the cold-pool bottom starts from a much lower base, and solar gain can't make up the deficit. So never put a year-round seating platform in a bowl, even if it looks sheltered.

What materials actually do: thermal mass, reflectors, and transparent shields

Thermal mass – Using heavy materials to soak up daytime heat and release it at night is the oldest passive trick in the book. I like dark basalt gravel and rust-colored brick. On a clear January afternoon, my thermometer gun read 5–10°F on the sunny face of a 4-inch basalt slab, while the adjacent snow surface was still at -5°F. That's a single reading from one day—not a long-term average—but it gives you the idea.

Concrete holds heat well, but if it lacks air-entrainment and proper freeze-thaw mix, water seeps into pores, freezes, and spalls the surface in a few winters. A concrete seat wall near Cordova showed about ¼ inch of surface crust loss after two years.

I switched to dry-stacked gabion walls filled with crushed basalt—they drain freely, and frost damage is almost zero. The galvanized wire cages cost more upfront, but maintenance is negligible. You can usually source stone locally; in south-central Alaska, crushed rock runs roughly $30–60 per ton, depending on supplier and haul distance.

Reflective surfaces – A 2-foot-high wall on the north side of the seating area, painted with exterior white paint, can bounce low-afternoon sun onto people's knee level—right where it warms your body. I tested aluminum sheet vs. painted wood. Aluminum reflects more but creates harsh glare. I went with white-painted wood.

Material cost (board plus paint) runs about $3–5 per square foot, depending on local lumber prices. That's cheaper than any heater, and it uses no energy. But remember: it only works when the sun is actually shining. It's a bonus, not a standalone solution.

Transparent windbreaks – I've tried single-pane glass, greenhouse film, and 16-mm twin-wall polycarbonate. If you're building something permanent, I only recommend polycarbonate—at least 16 mm thick. In the U.S. market, it's roughly $3–5 per square foot (maybe higher in Alaska), several times the cost of film, but it stands up to 60-mph gusts without tearing, and its insulation value is far better than single glass.

One critical detail: you must add an insulating night curtain. On a Fairbanks project, we installed a manually operated reflective foam-fabric curtain—pull it down at dusk, roll it up in the morning. Without it, that transparent shell turns into a radiator after 4 p.m. and sucks out all the day's stored heat. I have to be honest: I haven't long-term tested the curtain's roller mechanism below -30°F. It does occasionally freeze up and needs a shot of silicone spray.

Wind protection: sometimes more important than the sun

On a campground project along the Denali Highway, I spent way too much effort designing a south-facing glass screen to maximize winter solar gain. The first winter flopped—not because of sunlight, but because a west-facing katabatic wind stripped away every bit of warmth. Our onsite wind logs showed frequent afternoon gusts of 15–20 mph, making the wind-chill feel about 20°F colder than the actual air temperature.

We added a horizontal wood slat screen on the west side, with about 40% openness (2×4 fir slats spaced one slat-width apart). After that, wind speed inside the seating area dropped to 3–5 mph, and on a -10°F but sunny afternoon, you could sit and finish a cup of coffee. That case locked in a principle for me: in Alaska, wind protection is at least as important as solar harvesting. If you can only afford to do one, do wind first.

Living windbreaks take time—but you can use temporary structures in the meantime. I often put up rot-resistant burlap or commercial wind-break fabric on steel pipe frames, then remove them once white spruce or larch grow tall enough. A spruce seedling in interior Alaska takes about 4–6 years to create a meaningful downwind zone. If you don't have that patience, just use fabric. It's far better than sitting in the raw wind.

Active heating: when the sun just isn't enough

No matter how clever your passive design, a string of overcast January days in Anchorage will zero out all your gains. Active heat isn't a backup—it's a necessity.

My first choice is electric infrared heaters. They warm people and surfaces directly, not the air, so they work best in calm or light-wind conditions. A 1500-watt unit retails for about $80–200 (brand-dependent). At Anchorage's residential electricity rate of roughly $0.18–0.25/kWh, running one for an hour costs about $0.27–0.38. Inside a wind-screened four-person nook, that can keep things tolerable at -10°F.

Propane patio heaters (about 40,000 BTU) cost about the same to buy, but a 20-lb tank on high lasts only 8–10 hours, and refill costs vary widely by season and supplier. Over the long run, they're usually more expensive than electric, and their efficiency tanks in wind. I only use propane in fully open, temporary setups.

There are also solar-powered heated seat pads on the market. I tested one outside a warehouse in Juneau: in full sun at 1 p.m. on a December day with air temp around 25°F, the seat surface hit about 50°F (a single test, not a spec). That felt noticeably warmer than cold plastic. But battery life and snow on the PV panel keep it from being a primary heat source. Don't rely on it without a grid or generator backup.

What we can learn from real-world cases

The DOE's Office of Scientific and Technical Information (OSTI) has a report titled "Passive solar design takes hold in Alaska" (OSTI ID: 5774531). It documents three public buildings in Alaska that use R-60 insulation, masonry thermal mass, and south-facing atria. One of them saw a big efficiency jump after a snowfall—the ground snow reflected extra light into the atrium, warming the floor noticeably. That echoes the snow-reflection effect we talked about.

But these buildings share a common flaw: summer overheating. Some interior spaces topped 90°F on May afternoons. For outdoor seating, that means a winter-perfect sun trap can become an oven in June, when the sun angle climbs above 50°. The fix is simple: use removable shade sails. Take them down in winter, put them up in May. A 6×6-foot ready-made sail runs about $40–80 (depending on fabric and brand), and it keeps your stone wall from turning into a heat radiator during long summer days.

Places like Middle Way Café in Anchorage and Exit Glacier Salmon Bake near Seward have outdoor seating that mostly relies on existing building shelter. They're not designed to actively harvest low-angle winter sun. The reality is, no one in Alaska—as far as I know—has built a fully integrated outdoor space that combines passive solar, wind protection, thermal mass, and active heat all in one package. That's both a challenge and an opportunity.

Pre-construction checklist

These aren't rules—they're questions you must answer before you break ground. If one answer is fuzzy, pause.

Did you map the site's actual shadow pattern around December 21, marking it hour by hour?

Is the seating oriented between south and southwest, within 15° of due south?

Does the floor or wall use dark thermal-mass material, and is it free of furniture or snow piles that block it?

Can you strategically keep snow on the south side as a natural reflector?

If you add a transparent enclosure, does it have a night insulation curtain or closeable panels?

Is there a windbreak on the prevailing wind side, with about 40% permeability?

Do all foundations go below your local frost depth (often >4 ft), or use an engineer-approved frost-proof design?

Is your active heater's power or fuel supply independent and reliable? Have you estimated running costs for your expected winter usage?

Can any roof or cover handle the local 50-year snow load, and is it steep enough to shed snow naturally?

Do you have removable shade components ready for the long, high-sun days from May to August?

In Alaska, no two sites share the same winter microclimate. Your sun angles, snow drifts, and wind channels are unique. Take your measuring tools outside, stand there during the coldest season for a few hours, and note every board, every shadow, every gust. Those on-site facts will tell you far more than any guide ever could.

FAQs

Q: My yard's south side is completely blocked by a neighbor's house—no direct sun at all on the solstice. Is there any point in trying solar gain?

A: If direct sun is fully cut off, passive solar isn't an option. At that point, you're down to wind protection and active heat, with maybe a tiny bit of scattered light off snow. In a similar case, I moved the seats to the east side of a garage wall to catch a short morning sun window. It wasn't nearly as good as a south exposure, but it was the only usable daylight that site had. If you can't get sun, prioritize shelter from wind and a reliable heat source.

Q: What's a cost-effective, durable material for a thermal-mass retaining wall?
A: Dry-stacked gabion baskets filled with crushed basalt or granite is my current favorite. Stone is local—roughly $30–60/ton in south-central Alaska (prices vary). The galvanized baskets cost more upfront, but they drain freely, resist frost heave, and need almost no maintenance. A poured concrete or brick wall requires drainage and a frost-proof footing, and its long-term freeze-thaw performance often falls short of a well-built gabion.

Q: How much difference does an infrared heater actually make at -20°F or colder?
A: In a sheltered, low-wind spot, it can significantly cut radiative heat loss from your body—enough to sit for 15–20 minutes without that painful cold bite. But it doesn't warm the air, so your back and unexposed sides stay frigid. At -30°F, I've used two 1500-watt units facing each other, and people could sit for about 20 minutes with a hot drink—then they had to get up and move. That's a single personal observation, not a product claim. It's not a comfort system; it extends "impossible" to "briefly tolerable."

Q: Can I build a small wood platform without deep foundations and avoid frost heave?
A: If you have naturally well-drained gravel soil, you can try a compacted gravel pad with 2 inches of rigid foam insulation underneath to limit frost penetration. But I've only tested this on temporary structures—it's not an engineered solution for permanent use. For anything permanent, consult a local licensed engineer. Frost heave can turn a flat deck into a roller coaster in one winter, and that's a risk you shouldn't take without professional advice.

Disclaimer

This article reflects the author's personal experience and field observations on specific sites. It is not intended as general engineering advice for all locations, soil types, or climate conditions. Outdoor structures involve life-safety concerns—including snow loads, structural stability, and fuel-burning appliances. Always consult a licensed local engineer or architect before construction, and follow all applicable building codes and safety regulations. The author assumes no liability for property damage, personal injury, or any other loss arising from the use of this information.

References

[1] Alaska Geophysical Institute, University of Alaska Fairbanks – "Daily Temperature Variations" (public education series).
Cited for: the minimal heating effect when sun is below 10° altitude, and Fairbanks solstice solar altitude.

[2] Alaska Geophysical Institute, University of Alaska Fairbanks – "Winter Solstice" (public education series).
Cited for: Anchorage solstice solar altitude (~5°) and Utqiaġvik polar night conditions.

[3] U.S. Department of Energy, Office of Scientific and Technical Information (OSTI) – "Passive solar design takes hold in Alaska." OSTI ID: 5774531.
Cited for: documented performance of three Alaska public buildings with R-60 insulation, masonry thermal mass, and south-facing atria, including snow-reflection effects and summer overheating issues.

Note: All field-measurement data, cost estimates, and material performance observations in the text are drawn from the author's personal project records (2009–2025) and are included as experiential references, not as peer-reviewed scientific literature. The ~60% snow-reflection enhancement figure is cited from GI-related materials as a potential magnitude—actual gain varies with snow conditions and measurement methods. Retail prices are historical U.S. market quotes; check current local suppliers for current pricing.

About the author:

Dusty Rhoades

Builder without a fixed address. Over the past decade, he has constructed from the hurricane-prone coast of Florida all the way to the permafrost of Alaska, building outdoor facilities and providing accommodation and meals for farms, towns, and national parks. He only recommends materials that have survived a snowstorm or an entire rainy season right in front of his eyes. His advice is: "Your postal code is more authoritative than any design magazine."