Your best window to hike
UV, temperature, thunderstorm timing, and air quality — scored for hikers who spend hours above the treeline.
Why hikers need GoWindow
UV changes hour by hour
Each hour in the chosen window is scored with its forecast UV index. High UV can lower the score and trigger a warning.
Thunderstorms override a nice forecast
Forecast thunderstorms and active severe-weather alerts sharply reduce the hiking score. Afternoon rain risk also adds a caution.
Heat stress, not just temperature
GoWindow estimates WBGT from temperature, humidity, UV, cloud cover, and daylight, then applies a heat penalty when conditions become risky.
What the hiking score weighs
Every hour uses its own UV index; high values can lower the score.
Air temperature is scored against the hiking range, with a separate extreme-cold penalty.
Forecast thunderstorms and active severe-weather alerts sharply reduce the score.
Rain from earlier forecast hours that day estimates trail wetness; snow, ice, and hail receive a separate penalty.
Hiking applies an exposed-ridge adjustment to forecast wind before scoring it.
AQI above the Good band can lower the score when data is available.
When GoWindow helps hikers
Starting early to beat afternoon thunderstorms on an exposed ridge
Choosing between a Saturday and Sunday for a day hike based on UV and heat
Deciding whether smoke haze means a bad air day on trail
Finding a 3-hour window for a short hike between weather systems
From the blog
AQI and your lungs: what the air quality number means when you're running
When you run, you breathe ten to twenty times harder than at rest. That changes how air pollution lands in your body. Here's what runners should actually do with the AQI number.
Dew point vs humidity: why your weather app lies to runners
Relative humidity tells you almost nothing about how a run will feel. Dew point does. Here's why the distinction matters and how to use it.
When to hike before a thunderstorm: plan the window, not the summit
How to choose a hiking window when thunderstorms are possible, with a simple plan for turning around before the route becomes exposed.
Why Timing Matters More Than Temperature
Most people check the temperature before heading out. The best outdoor sessions depend on a narrow window where several conditions line up — not on one number.
