loop4d

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.