On a hot afternoon the map’s shortest line is usually the one that stays in the sun. You feel it on the pavement before you check the clock: a street that looked fine on the phone turns into a corridor of glare, and the “faster” option costs you shade you could have kept.
Shadeside exists for that mismatch. It does not tint a city with a generic heatmap. It asks, for this minute, which façades and canopies actually throw shadow on the walk you are about to take — then it prefers that walk, even when it is a little longer.
The shadow a building really casts
Building heights come from OpenStreetMap. The sun position is the NOAA solar algorithm, computed on the phone for your exact place and time. Together they project the umbra that those volumes would throw — not a cartoon blob, not yesterday’s average, but this block at 15:20.
Trees count. On a hot afternoon a mature canopy shades a pavement more reliably than a low-rise block. Street trees, avenues and woodland are part of the same geometry, so a route can duck under an allée instead of hugging a glass wall that looks “urban” and offers almost nothing.
Every building casts the shadow it actually casts.
Pick the shadier way, then stay on it
You choose a destination the way you would in any walking app. Shadeside compares candidates by shade as well as time, using the trade-off you set: how many extra minutes the cooler line is worth. If you step off the path, it updates and keeps you on the shadier side rather than snapping you back to the sunlit shortcut.
You can also plan for later: see where the shade will lie this evening, and download the city before you leave so routing still works without a signal. After that first download the sun is computed on device — no account, no server in the loop while you walk.
Live guidance sits on the Lock Screen and in the Dynamic Island: which side to keep to, how much shade is left, how far to your stop. You should not need to unlock the phone to check whether you are still in the cool.
Send the walk when you are done
When the route ends, Shadeside can turn it into a card: the map, the share of the walk that stayed in shade, and how that stacked up against the regular way. Ready to send, without a screenshot collage.
That is the whole product idea: the shortest way is not the coolest way, and the coolest way should be honest about the city that is actually standing there. Shadeside is on the App Store for iPhone.