Frequently Asked Questions
What is ShelterCast?
ShelterCast is a free web tool that builds elevation-adjusted weather forecasts for the Appalachian Trail. Pick a start and finish crossing for a night-by-night trip outlook, or pick a single shelter for a 10-day outlook at that spot. It works for any length of hike, from a day trip to a 300-mile section.
Is ShelterCast free?
Yes. There is no account, no sign-up, no ads, and no charge. A modest daily per-visitor forecast limit keeps the tool free for everyone.
How does ShelterCast forecast a multi-day trip?
It samples your route at its lowest, middle, and highest elevations, then forecasts each of those trail points for every day of the trip. The report shows the spread across them, because ridges run colder and windier than gaps, and that elevation swing usually matters more than how far along the route you walk in a day. Whichever condition is worst across the samples drives each day's summary, so the report errs toward the rougher end rather than the average.
Does a trip forecast tell me which shelter I will sleep at each night?
No. Pace varies too much between hikers to place anyone at a named shelter on night three, so a trip forecast covers the shelters and gaps you pass as elevation bands, not a campsite per night. For weather at one specific shelter, use Forecast by Shelter, which gives a 10-day outlook at that shelter's own location and elevation.
How accurate is a forecast more than 7 days out?
Beyond 7 days, ShelterCast shows 5-year historical averages (climatology) instead of a live forecast, and labels those days clearly. Inside the 7-day window it uses live hourly forecast data. Climatology cannot predict a specific storm, but it is an honest picture of what that stretch of trail is typically like at that time of year, which is the useful signal when your start date is still weeks away.
Why is my ShelterCast forecast different from the town forecast?
Elevation. Air cools roughly 3.5°F for every 1,000 feet gained, and trail towns sit in valleys, so a town forecast can read 10-20°F warmer than the ridge above it. ShelterCast requests weather at each trail point's actual elevation, which is usually the difference that matters most on the Appalachian Trail.
What data does ShelterCast use?
Weather comes from Open-Meteo, queried at each waypoint's elevation. Severe weather alerts come from the National Weather Service. Shelter and crossing locations come from National Park Service / Appalachian Trail Conservancy data and TopoFusion trail data. Locations are approximate: good enough for weather, not for navigation.
Curious how big the elevation effect really is? See how much colder it gets at elevation on the Appalachian Trail, or read more about the tool on the about page.