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 adds up on long days
A 5-hour hike at moderate UV delivers a bigger dose than most people realize. The score tracks cumulative exposure across the whole window, peak index included.
Thunderstorm timing is everything
Mountain weather turns fast. GoWindow shows when convective activity is expected so you can summit before it arrives, not during.
Heat stress at altitude
Thinner air, stronger sun, and sustained effort create heat stress that isn't obvious from the valley forecast. The score accounts for exertion level and exposure duration.
What the hiking score weighs
Cumulative UV load across the window — especially important above treeline.
Comfortable hiking range is narrower than you'd think when carrying a pack uphill.
When convective storms are expected; early starts can avoid afternoon lightning.
Wet trail conditions and visibility on ridges.
Exposed ridgelines and summits feel very different from sheltered valley wind.
Wildfire smoke and haze reduce visibility and air quality — both matter on trail.
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.
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.