About ShadeDial

Why it exists

I have a family, an RV, and a long history of eating lunch in direct sunlight.

Every trip went the same way. Put the awning out, sit down, and an hour later the sun has moved and found us again. Move the chairs — it finds us. Move the table — it finds us. You’d have thought I was Dracula, the way I hunted shade. I am not. I just wanted to finish a sandwich before it went warm.

The maddening part is that it was all decided months earlier, by a site number I picked off a map. C20 or C24 — one has trees to the west, one doesn’t, and nothing on the reservation page says which. So I worked it out. Site by site.

How it works

1. 1. Find every site. Campsite coordinates and attributes come from the park services themselves — 6,624 individual numbered sites across 33 campgrounds in 21 national parks.
2. 2. Build a horizon for each one. For every site we look outward in 180 directions and record how high the sky is blocked — by canyon walls and ridgelines up to 16 km away, and by tree canopy nearby.
3. 3. Run the sun across it. The sun’s path is stepped through the day in 15-minute intervals and checked against that horizon. What comes out is when the sun reaches each site and when it leaves — the shade window you actually plan a day around.

Data sources

• Campsite positions & attributes— Recreation.gov campsite records (US) and Parks Canada open data via OpenStreetMap (Canada). Ratings shown as “park-rated” come straight from Recreation.gov, not from us.
• Terrain — Mapzen / AWS Open Data terrain tiles (bare-earth elevation).
• Tree heights — ETH Zurich Global Canopy Height model, 10 m resolution, satellite-derived, 2020.
• Sun position — standard astronomical formulas (NOAA), accurate to a fraction of a degree.
• Imagery — © Esri, Maxar, Earthstar Geographics.

Where this is wrong

Worth reading before you trust a number. We would rather tell you the limits than have you find them at the campsite.

• Trees are the weak link. The canopy data is 10 m resolution, which cannot resolve a campground — pads, loop roads and trees are interleaved below that scale. We tested how much this matters by re-running everything with a different assumption about how much clearing surrounds a pad: at forested campgrounds it moved the daily totals by hours. Rankings held up better than absolute figures, so trust “shadier than that one” more than “exactly six hours”.
• Terrain is solid.Canyon walls and ridgelines don’t move, and that part of the model is reliable. Desert and canyon campgrounds are our most trustworthy pages for that reason.
• The canopy data predates the fires. It was captured in 2020. Campgrounds hit by the 2024 Jasper wildfire are computed from terrain alone and carry a warning on the page — those figures are an upper bound on sun, so they will never promise you shade that burned.
• Times are rounded to the half hour and written as “around”, because the inputs underneath don’t support finer than that.
• Clear sky only. Weather is not included, and figures are computed for the 15th of every month, all year.
• Winter in deep valleys is the least certain. Where high walls and tall trees ring a campground — Yosemite Valley above all — the low late-fall and winter sun barely clears them, so those months can read as little or no direct sun. Usually that is genuinely true — the valley floor really is shaded for much of winter — and it is also where the tree data matters most, so in dense forest give the deep-winter figures a little more room than the rest.

Independence

ShadeDial is an independent planning tool, built and run by one person — me. It is not affiliated with the National Park Service, Parks Canada, Recreation.gov, or any booking provider, and it earns no commission on anything you book. Nobody pays for placement here, and nobody can.

Common questions

Is this an official park service site?

No. ShadeDial is independent and not affiliated with the National Park Service, Parks Canada, Recreation.gov, or any booking provider. Reservations always happen on the official sites — we just link to them.

Can I book a campsite here?

No, and we don’t want to. ShadeDial is for the part that happens before booking: working out which site numbers you actually want. The booking button sends you to the official reservation system.

Is it free? What's the catch?

Free, no account, no ads, no affiliate commission — the reservation systems don’t pay any. It costs about $25 a year in domain fees and some hosting, which is cheap enough to keep running while we find out whether anyone wants it.

How accurate is it, really?

The sun’s position is exact. The terrain is good. Trees are the weak link — see the accuracy section below, which spells out exactly where the model struggles. Treat every figure as an estimate and verify with the park.

My campground isn't here. Will you add it?

Search for it anyway — every search that finds nothing is recorded, and that list is how we decide what to add next. Or email us and say which one.

I camped somewhere and the shade was wrong.

Please tell us. Every site page has a thumbs up/down, and that feedback is the only way we can find the sites we’ve got wrong. It is genuinely the most useful thing anyone can send.

Contact

It comes straight to me and I read all of it. One person, so a real reply — usually within a day or two.

• The shade was wrong →

  Tell me the campground and site number, roughly when you were there, and what the sun actually did. This is the single most useful thing anyone can send.

• Add a campground →

  Which one, and I'll look at what data exists for it. Requests are how I decide what to build next.

• Something's broken, or an idea →

  Bugs, confusing wording, a feature you wish existed — all welcome.