Your phone is probably the most powerful safety tool in your hiking kit — and you might not even be using it that way.
Most hikers download AllTrails, check the weather on whatever default app came with their phone, and call it good. But if you're hiking in Colorado specifically, there are free tools built for this state's unique challenges: fast-moving afternoon thunderstorms, wildfire smoke that can roll in overnight, avalanche danger that persists well into summer, and remote terrain where your cell signal disappears the moment you need it most.
I've tested a lot of apps over the years, and these are the eight I check before every hike. They're all free, they all work on iPhone and Android (with a couple of exceptions I'll explain), and together they cover the biggest safety gaps most Colorado hikers don't even know they have.
1. COTREX (Colorado Trail Explorer)
What it is: COTREX is Colorado's official trail app, built by Colorado Parks and Wildlife and the Department of Natural Resources. It maps over 39,000 miles of trails across the state using data from more than 230 land managers — federal, state, county, and local agencies all feeding into one system.
Why it beats a generic trail app for Colorado: Unlike AllTrails or Gaia GPS, COTREX only shows information from official sources. That means no unreliable crowdsourced data or outdated trip reports from someone who hiked the trail three years ago. When a trail is closed for wildlife protection, road construction, or wildfire, COTREX shows it — often before any other app does.
Here's what makes COTREX especially useful:
- Real-time closures and advisories from over 36 agency partners, including seasonal wildlife closures that are mandatory and enforceable
- Wildfire alerts integrated directly into the map so you can see active fire impacts on your route
- Avalanche forecasts from the Colorado Avalanche Information Center (CAIC), added through a recent partnership
- Free offline maps that are lightweight and easy to download before you head out
- Activity-based filtering so you can see which trails allow hiking, biking, horseback riding, or motorized use
COTREX is the only app in Colorado that displays all seasonal wildlife closure information in a single place. If you've ever wondered whether a trail is open or closed for elk calving season or wintering bighorn sheep, this is where you find out.
Download: Free on iOS and Android, or use the web version at trails.colorado.gov.
Want to go deeper on GPS tools? Check out my guide to the 10 best GPS devices and apps for navigating Colorado 14ers and my comparison of GPS devices vs. smartphone apps for trail navigation.
2. Windy.com
What it is: Windy.com is a free weather visualization app that shows animated, real-time weather data on a global map. It pulls from multiple professional forecast models — including ECMWF (the European model, widely considered the most accurate), GFS, and ICON — and lets you toggle between them to compare predictions.
Why it matters for mountain weather: The default weather app on your phone tells you it'll be 75°F and sunny in Denver. That's great, but at 14,000 feet the temperature could be 35°F with 40 mph gusts and a thunderstorm rolling in by noon. Standard weather apps aren't built for the mountains.
Windy lets you:
- Watch approaching storm cells in real time using animated radar — critical during Colorado's afternoon thunderstorm season (roughly June through September)
- Check wind speeds and direction at ridge-level altitude, not just at the surface — this is the difference between a comfortable summit and a dangerous one
- Scroll through the forecast hour by hour so you can identify your weather window (most Colorado hikers aim to be off the summit by noon)
- View lightning potential using the CAPE (Convective Available Potential Energy) layer, which helps you judge thunderstorm risk before the clouds even build
The free version of Windy.com includes everything most hikers need. There's a premium version, but you won't need it for pre-hike planning.
Download: Free on iOS and Android, or use it in your browser at windy.com.
Important note: There are two apps with "Windy" in the name. You want Windy.com (by Windyty, SE — the Czech company). There's a separate app called "Windy.app" that's geared more toward water sports. Both are decent, but Windy.com is the better tool for mountain weather and storm tracking.
Concerned about NOAA's future? I covered why planned layoffs at NOAA could threaten the free weather forecasts we all rely on.
3. AirNow (EPA)
What it is: AirNow is the EPA's official air quality monitoring app. It shows you the current Air Quality Index (AQI) for any location in the United States, with a special focus on wildfire smoke through its built-in Fire and Smoke Map — a tool developed in partnership with the U.S. Forest Service.
Why Colorado hikers need it: If you hiked in Colorado during the summers of 2020, 2021, or 2023, you already know what wildfire smoke can do. One day the sky is blue; the next day you can't see the mountains from downtown Denver. Now imagine doing intense physical activity at high altitude in that air.
Here's the thing most people don't think about: exertion at altitude already strains your respiratory system. When you add poor air quality on top of that, you're compounding the risk. Breathing harder means pulling more particulate matter deeper into your lungs. The AQI might read "moderate" in town but feel much worse when you're gasping at 13,000 feet.
AirNow helps you make informed decisions by showing:
- Real-time AQI readings from official EPA monitoring stations across Colorado
- The Fire and Smoke Map, which layers data from permanent government monitors, temporary monitors, and thousands of PurpleAir community sensors for much denser coverage
- Smoke plume visualization so you can see where wildfire smoke is drifting — and where it's headed
- AQI forecasts for later in the week, helpful for planning weekend hikes
- Health recommendations based on current conditions, including guidance for sensitive groups
Download: Free on iOS and Android, or visit airnow.gov. For wildfire smoke specifically, go straight to the Fire and Smoke Map.
4. CAIC (Colorado Avalanche Information Center)
What it is: The CAIC app gives you the Colorado Avalanche Information Center's avalanche forecasts on your phone — including zone-by-zone danger ratings, current avalanche problems, detailed forecast discussions, and mountain weather forecasts.
Why it's not just for skiers: A lot of hikers think avalanche information is only relevant in winter and only for backcountry skiers. That's a misconception that gets people into trouble. Avalanche danger on Colorado's 14ers can persist well into June and return as early as October. If your route crosses snowfields above treeline — and many popular 14er routes do in spring and early summer — you need to know what the snowpack is doing.
Colorado leads the nation in avalanche fatalities. Since 1950, avalanches have killed more people in this state than any other natural hazard. The CAIC exists to help you avoid becoming a statistic, and their app makes that information accessible anywhere.
The app lets you:
- View current avalanche forecasts by zone, with clear danger ratings from Low to Extreme
- Read the detailed forecast discussion to understand why the danger level is what it is — not just what it is
- Check mountain weather forecasts tailored to Colorado's high country, which are often more useful than generic NWS forecasts for planning above-treeline travel
- Submit field observations directly from your phone, contributing to the forecasters' picture of current conditions
- Access new 2026 tools including a Weather Station Map display showing snowfall, temperature, and wind data from hundreds of stations statewide
Download: Free on iOS and Android. Supported by the Friends of CAIC, a nonprofit that funds CAIC's forecasting operations — consider donating if you use the backcountry.
New to avalanche safety? Start with my guides on types of avalanches and early-season avalanche hazards. And for the full story on CAIC's integration with COTREX, read Avalanche Forecasts Now Available on COTREX App.
5. iPhone Emergency SOS via Satellite
What it is: If you own an iPhone 14 or newer, your phone can send emergency SOS messages through satellites — even with zero cell service. This feature is currently free (Apple has extended the free period through at least late 2026, with no pricing announced yet) and is built directly into iOS. You don't need to download anything.
Why it matters: Cell coverage in Colorado's mountains is unreliable at best and nonexistent at worst. Most trailheads above 10,000 feet have spotty service, and once you're on the trail, you're often completely off-grid. If you twist an ankle in a remote basin or get caught in a storm above treeline, your phone is useless for calling 911 — unless it can talk to a satellite.
When you trigger Emergency SOS via Satellite, your iPhone walks you through a short questionnaire about your situation (injuries, number of people, etc.), bundles that information with your GPS coordinates, and transmits it to Apple's satellite relay center, which forwards it to the nearest 911 dispatch. The system also notifies your emergency contacts and shares your location with them.
Key limitations to understand:
- It's not instant. You need a clear view of the sky and may need to slowly pan your phone to find a satellite. Trees, canyons, and heavy cloud cover can interfere.
- It's text-only. You can't make voice calls via satellite. Communication happens through short text exchanges.
- It requires an iPhone 14 or newer. Older iPhones don't have the satellite hardware. Some newer Android phones are beginning to offer similar features, but availability varies by manufacturer and carrier — check your specific device.
- It's not a replacement for a dedicated satellite messenger. If you regularly hike in remote terrain, a Garmin inReach or similar device offers two-way messaging, location tracking, and a purpose-built SOS button that doesn't depend on your phone's battery. I have a full breakdown of Garmin inReach subscription plans if you want to explore that option.
That said, for the average day hiker on a Colorado 14er, having satellite SOS capability built into the phone you're already carrying — at no extra cost — is a genuinely significant safety upgrade.
6. Weather.gov Point Forecasts (NWS)
What it is: Weather.gov is the National Weather Service's official forecast site. It doesn't have a dedicated mobile app, but you can pull up a highly localized "point forecast" for any GPS coordinate in the country — including the summit of the 14er you're climbing tomorrow — and save it as a shortcut on your phone's home screen.
Why it complements Windy: Windy is the better tool for visualizing storms — watching cells move across the map in real time and comparing forecast models. But Weather.gov gives you something Windy doesn't: a text-based forecast written by a real NWS meteorologist. These are the same forecasts that search and rescue teams, land managers, and backcountry rangers use to make operational decisions.
The NWS point forecast tells you, in plain English, things like "Isolated thunderstorms likely above 12,000 feet after 1 PM" or "Winds gusting to 50 mph on exposed ridges." That specificity is hard to get from a model-based visualization alone.
Here's how to set it up:
- Go to weather.gov on your phone's browser
- Enter your location or click the map to drop a pin on the specific area you'll be hiking — you can even pin a summit or trailhead
- Once the forecast loads, use your browser's "Add to Home Screen" option to save it as a quick-access shortcut
- You can save multiple locations — one for your trailhead, one for summit elevation, one for home
The future of these free forecasts isn't guaranteed. I covered why planned layoffs at NOAA could threaten the weather data we all depend on.
7. What3Words
What it is: What3Words divides the entire planet into 3-meter squares and assigns each one a unique three-word address. Open the app, and it instantly shows you the three words for wherever you're standing — something like "table.lamp.forest." Give those three words to a 911 dispatcher or SAR team, and they can pinpoint your location to within about 10 feet.
Why it matters on the trail: Picture this: you've fallen and injured your knee in a basin below treeline. You have enough cell signal to make a call, but when the dispatcher asks "where are you?" — what do you say? "Somewhere near a lake below the ridge" isn't going to cut it. And reading out GPS coordinates like "39.6295 north, negative 105.8174 west" under stress, possibly in pain, is harder than you think.
Three words are easy to say, easy to hear, and hard to get wrong. That simplicity is the whole point.
A few things worth knowing about What3Words:
- It works offline. The three-word grid is stored locally on your device, so it functions through GPS even without cell service. You still need cell signal to call someone, but the location itself doesn't depend on a network connection.
- Emergency services are adopting it. Over 85% of rescue services in the UK use What3Words, and adoption is growing among US agencies. Some 911 dispatch centers in the US will ask callers to download the app on the spot if they can't describe their location.
- It's not perfect. Some SAR professionals have raised concerns about similar-sounding word combinations causing confusion, and it's a proprietary system rather than an open standard. But for most hikers, it's a massive improvement over trying to describe your location by landmarks alone.
Download: Free on iOS and Android.
For more on how Colorado's SAR system works and why it matters, read my coverage of the new interagency search and rescue agreement taking effect in 2026.
8. 14ers.com App
What it is: The official app from 14ers.com — the most established Colorado 14er resource online. It puts the site's detailed route descriptions, route maps, route photos, trailhead information, and user-contributed condition reports into a mobile format that works offline in the backcountry.
Why it earns a spot on this list: If you're climbing Colorado's 14ers, you've probably already used the 14ers.com website to research routes. The app takes that same trusted information — covering 60+ routes across all 58 peaks — and makes it available when you're standing at a trail junction at 12,500 feet with no cell service, trying to figure out which cairn to follow.
What you get in the free app:
- Complete route descriptions for every standard route on every Colorado 14er, with detailed turn-by-turn narrative, photos, and difficulty ratings
- Route maps with the 14ersTopo base layer — purpose-built topographic maps with high-resolution contour lines, faster than loading generic tiles
- Real-time condition reports from other hikers, pulled from the 14ers.com website — this is where you find out about snow on the trail, rockfall hazards, road closures, and trailhead conditions from people who were just there
- GPS track recording and waypoints so you can record your own route and export it as a GPX file
- Offline access — download the route info before you leave and it's available without a connection
The condition reports alone make this app worth having. Before any 14er attempt, I check 14ers.com to see what the most recent hikers have reported about snow levels, trail conditions, road access, and weather they encountered. It's crowd-sourced intel from people who actually hike these peaks regularly.
Download: Free on iOS and Android.
If you're just getting started with 14ers, check out my complete guide to Colorado's 14ers and the full difficulty rankings to help you choose your first peak.
What About AllTrails, Gaia GPS, and Other Paid Apps?
Let me be clear: I'm not saying you shouldn't use AllTrails or Gaia GPS. They're both good tools, and I use them myself. AllTrails is great for browsing trails and reading trip reports, and Gaia GPS has excellent topographic maps and route planning features.
But here's the thing — both of these apps put their best features behind paid subscriptions. AllTrails+ costs about $36 per year for offline maps and route tracking. Gaia GPS runs around $40 per year for premium map layers.
The eight tools in this article are completely free and cover safety-critical functions that neither AllTrails nor Gaia handles well: official trail closures, wildfire smoke monitoring, avalanche forecasts, human-written weather forecasts, precise emergency location sharing, and satellite communication. Think of them as the foundation layer. Whatever paid app you prefer goes on top.
One More Thing: Apps Don't Replace Preparation
I'd be doing you a disservice if I didn't say this clearly: no app replaces sound judgment, proper gear, and real preparation. Your phone battery can die. Your screen can crack. You can lose signal at the worst possible moment.
These apps are powerful tools for planning and monitoring, but when you're actually on the mountain, you still need to carry the Ten Essentials, know how to prevent altitude sickness, bring the right gear for a 14er, and make conservative decisions when conditions change.
The best safety device is still the one between your ears. Use it.
Quick Reference: Your Pre-Hike App Checklist
- 📍 COTREX — Check for closures and download your offline map
- 🌦️ Windy.com — Review the hourly forecast at summit elevation and watch for afternoon storm potential
- 💨 AirNow — Check the AQI and Fire and Smoke Map the morning of your hike
- 🏔️ CAIC — Review the avalanche forecast if your route crosses snow or steep terrain
- 🆘 iPhone SOS — Confirm your emergency contacts and Medical ID are up to date
- 🌤️ Weather.gov — Read the NWS point forecast for your summit elevation
- 📌 What3Words — Know your three-word address at the trailhead and share it with your emergency contact
- 🥾 14ers.com — Check recent condition reports and bookmark your route for offline access
Safe travels on the trail.
