ArcPace: Weather for Runners
Plan the best time to run
Only for iPhone
Free · In‑App Purchases
iPhone
Race morning, ten days out: every hour scored 0–100 for running, with the pace cost and what to wear. Open any day hour by hour.
ArcPace turns the forecast into the one question a runner asks: when should I run, and how will it feel?
EVERY HOUR, SCORED
Each hour of the next two days gets a run score out of 100 and a pace impact in seconds per mile or km, measured against an ordinary day. Heat and humidity slow you down; a cool morning can make you quicker. The score comes from temperature, dew point, wind and gusts, rain and altitude. Thunderstorms and freezing rain cap it outright. The UV index and WBGT heat stress (the flag system used at races) are shown alongside, described rather than scored.
YOUR BEST WINDOW AT A GLANCE
Tell ArcPace when you can actually run, and it ranks those windows. Each one says what to wear and what to carry.
TEN DAYS AHEAD
Each of the next ten days scored from its worst hour to its best. Open one for its best run, the day hour by hour, and what to wear.
WHAT THE WEATHER COST YOU
With read-only access to Apple Health, ArcPace scores your last sixteen weeks of runs against the weather they were run in. A slow July run reads "Humidity set this pace, not you", with what it was worth on an ordinary day. A calendar of those weeks, a fitness trend with the weather taken out, and weather-adjusted bests.
ALSO
• A Home Screen and Lock Screen widget with this hour's score and your best window ahead
• An optional notification with tomorrow's best window
• A share card for any run
• Saved locations for travel planning
• Imperial or metric, light or dark, Reduce Motion and Dynamic Type respected
PRIVATE BY DESIGN
No account, no ads, no analytics, no server of our own. Your runs are read and kept on the phone; to score one, only its approximate place and hour go to Apple Weather. Your location goes only to the weather service: Apple Weather, or Open-Meteo as a backup.
ArcPace is free. If it earns a place in your routine, you can leave a tip from Settings.
- 10-day run forecast: each day's best and worst run score, at the bottom of Today. Tap a day to see it hour by hour, and drag along the chart to read any hour.
- Rain, read for what it does: on a muggy day it's the dew point, not the rain, that slows you, and Today says so. Cold rain counts colder, and heavy rain costs for footing.
- When the weather makes you faster, the pace bar says by how much: −12s/mi.
- The White heat flag is drawn white.
- Hourly sits under Run times and scrolls further with each swipe.
- arcpace.app links open the app, and Settings links to the running weather guides.
The developer, Stephen Chou, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Stephen Chou
- Size
- 47.2 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- In-App Purchases
Yes
- Tip: Toward new shoes $14.99
- Tip: A pack of gels $5.99
- Tip: Buy me a coffee $2.99
- Tip: Toward new shoes $14.99
- Tip: A pack of gels $5.99
- Tip: Buy me a coffee $2.99
- Copyright
- © 2026 Stephen Chou