SurfaceCast: Surface Temp

Air temperature tells you almost nothing about how hot the ground actually is. On a sunny summer afternoon, dark asphalt can run far hotter than the air, while grass a step away stays close to it. SurfaceCast lets you see that difference as a curve, hour by hour, before you go outside. Pick a place and a date, then add the surfaces you care about — asphalt, concrete, grass, bare soil, sand, a wooden deck, brick, a painted metal roof, a white or dark wall. Up to five at once, drawn on the same chart so you can compare them directly. WALLS AND SLOPES, NOT JUST THE GROUND Every surface has a compass direction and a tilt. Point a wall east and it warms through the morning; point it west and it peaks late in the day. Set a slope anywhere from flat ground to a vertical wall and watch the curve move. Four one-tap presets cover north, east, south and west walls. SHADE THAT BEHAVES LIKE REAL SHADE Mark the hours when a surface falls into shadow — say, shaded from 11:00. Sunlight drops immediately, but the temperature does not: heavy materials keep releasing stored heat and cool down gradually, exactly as they do outdoors. That lag is the whole point, and SurfaceCast models it. WHAT YOU GET • 24-hour estimated surface temperature for up to five scenarios • Live hourly weather for your location, or any place you search • Air temperature drawn alongside, so the gap is obvious • Sunrise, solar noon and sunset markers, plus shaded bands on the chart • Tap any hour for a side-by-side table: temperature, difference from air, sunlight on that surface, shade level and confidence • Peak temperature and the time it happens, for every scenario • Save scenario sets — "the back garden", "the dog walk route" — and reload them later with a new date • Celsius or Fahrenheit, and it works from a cached forecast when offline HOW IT WORKS SurfaceCast computes the sun's position for your place and time, works out how much sunlight lands on a surface at that angle and direction, then runs a heat balance in short internal steps: sunlight absorbed, heat lost to the wind, heat radiated to the sky, heat exchanged with the ground below and cooling from evaporation on damp surfaces. Each material carries its own absorptivity, emissivity and thermal mass, so heavy and light surfaces behave differently — as they should. These are physics-based estimates for observation, learning and curiosity. Real surfaces vary with thickness, construction, moisture, nearby reflections, local wind and the exact shape of the shadow. SurfaceCast is not a safety instrument and does not judge whether a surface is safe to touch or walk on — if that matters, measure it with an infrared thermometer.