One answer, not a dashboard
No pressure charts, no hourly scrolling. Gwhen names the time and tells you why in a sentence.
Know when to go.
Best time for outdoor plans. Gwhen reads the forecast and answers a single question — when to go. Precise time windows for cycling, running, walking, tennis and dinner outside.
Availability
Coming soonComing soon
Learn moreHow it works
Designed for iOS · Lock Screen, Dynamic Island and Live Activities
9:41
Wednesday, Aug 12
Today
Three good openings today. The morning one is the best you'll get this week.
Road RideExcellent
6:20–7:50 AM
Stroller WalkGood
5:40–6:30 PM
Tuned to your activity
A road ride and a stroller walk want different weather. Set thresholds once; Gwhen judges accordingly.
Honest when it's bad
When nothing is genuinely good, Gwhen says so — and shows the least-bad option instead of faking confidence.
The signature
A timeline that shows the window opening.
Closed, opening, ideal, closing. The recommended stretch lifts out of the day with a soft silhouette, so you read the shape of the morning before you read a single number.
Best window today
6:20–7:50 AM
5AM6AM7AM8AM10AM
6:20–7:50 AM
Cool temperatures, light wind and dry conditions make this today's strongest riding window. Wind picks up noticeably after 8.
How it works
Four steps from forecast to decision.
Gwhen does the interpretation a careful person would do by hand — every hour, for every activity, before you wake up.
- 01
Choose an activity
Road ride, run, stroller walk, tennis, dinner outside — or something of your own. Each one starts from a sensible profile.
- 02
Say what good means
Temperature range, wind tolerance, rain patience, how much daylight you need. Two or three taps, then never again.
- 03
Gwhen scores the day
Every interval in the forecast is graded Excellent, Good, Fair or Poor against your thresholds, then smoothed into continuous stretches.
- 04
You get one time
The strongest continuous stretch becomes the recommended window, with a one-line reason and the conditions that back it up.
9:41
Wednesday, Aug 12
Today
Three good openings today. The morning one is the best you'll get this week.
Road RideExcellent
6:20–7:50 AM
Stroller WalkGood
5:40–6:30 PM
The four condition states
Excellent
Everything lines up. Go.
Good
Comfortable, with one soft caveat.
Fair
Doable if you're motivated.
Poor
Gwhen won't pretend otherwise.
Pricing
Free to decide. Pro to plan.
No ads, no data resale, no upsell theatre inside the app.
Free
$0
One activity, today's window
- —One saved activity
- —Today's recommended window
- —Plain-language reasoning
- —Light and dark
Pro
$3.99
per month, or $29 a year
- —Unlimited activities
- —Seven-day outlook per activity
- —Custom thresholds and tuning
- —Lock Screen alerts and Live Activities
- —Multiple locations
FAQ
Questions
- Do I need Pro to get a useful answer?
- No. The free tier gives you a full, honest window for one activity every day. Pro is for people tracking several activities or planning further ahead.
- Where does the forecast come from?
- High-resolution hourly forecast data, re-scored locally against your own thresholds so the judgement is yours, not a generic weather grade.
- What happens on a bad weather day?
- Gwhen tells you plainly that nothing is good, and shows the least-bad option with a caveat rather than promoting a poor window.
- How accurate is the recommended window?
- As accurate as the hourly forecast underneath it. Gwhen refreshes through the day, and a window can shift or narrow as the forecast firms up — you'll see the change, not a stale answer.
- Can I track more than one location?
- Yes, on Pro. Each activity can carry its own location, so a home ride and a weekend trailhead are scored separately.
- Which activities are supported?
- Road ride, run, walk, stroller walk, tennis, dinner outside and more ship as starting profiles. You can also create your own and set exactly what good means for it.
- What does Gwhen do with my data?
- Nothing beyond giving you an answer. No ads, no data resale, no third-party trackers. Location is used to fetch a forecast, not to build a profile.
- Is it on Android or the web?
- Gwhen is designed for iOS first, including Lock Screen alerts, Dynamic Island and Live Activities. Other platforms aren't available yet.
- Can I cancel anytime?
- Yes. Pro is billed through the App Store — cancel in a couple of taps and you keep Pro until the period ends, then drop back to the free tier.
Go when it's good.
Add the activities you care about. Gwhen watches the forecast and tells you the one time worth clearing your calendar for.
Coming soonComing soon