SurfaceCast: Surface Temp
How hot does asphalt get?
$2.99 · Designed for iPad. Not verified for macOS.
Air temperature tells you nothing about the ground. Compare asphalt, grass, decking and walls hour by hour, and see how much colour alone changes.
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.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Yoshiaki Hirokawa, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Yoshiaki Hirokawa
- Size
- 4.2 MB
- Category
- Weather
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 32 more
- English, Arabic, Catalan, Croatian, Czech, Danish, Dutch, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Malay, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Slovak, Spanish, Swedish, Thai, Traditional Chinese, Turkish, Ukrainian, Vietnamese
- Age Rating
4+
- 4+
- Copyright
- © 2026 netflowers
