loop4d

You picked the route — loop4d picks the hour. See when your run or ride has the most shade or sun, with heat, wind and twilight, computed right on your phone.

loop4d adds the fourth dimension to route planning: time.

You already know your route. loop4d tells you WHEN to run or ride it — the hours with the most shade on a hot summer day, or the most sun in winter — so you can plan around the heat, the glare and the wind.

Open a GPX file (or share one from Strava, komoot, Garmin Connect or Files), pick a date, and loop4d walks the sun across your whole route, point by point, to find your best time to go.

HOW IT WORKS • Per-point sun & shade — for every part of your route, loop4d works out when the sun clears the ridges, trees and buildings around you. • Best windows — clear "best in shade" and "best in sun" time slots for your chosen day. • Weather & wind — temperature, rain, wind direction and twilight over your day, from a live forecast. • Replay — scrub through the day and watch your route light up shade, sun, headwind and tailwind, segment by segment. • Forward or reversed — flip the direction and loop4d re-picks the ideal start.

BUILT FOR RUNNERS & CYCLISTS Marathon training in July? Find the shaded hours. Chasing winter sun on the bike? Find the bright ones. Planning a long climb? See where the wind hits.

PRIVATE BY DESIGN loop4d runs entirely on your device — no account, no sign-in. Your route is analyzed right on your phone; loop4d only fetches public elevation and weather data to do the math.

Pick your route. We'll pick the hour.