Procedural Planet: Climate, Biomes & Sea-Level Lab

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Move the pointer over the map or globe to read the local climate.

Generating world…

Presets

Planet parameters

Axial tilt

Ocean fraction (sea-level percentile)

Surface gravity

Stellar flux (× Earth)

Greenhouse warming

Water availability

World seed

Display

Relief exaggeration (globe)

Live readouts

Zonal climate

Surface area by biome

Experiments

Test	Measured	Predicted	Err
Press a button to measure the current planet against its analytic prediction.

About

The science

Insolation. Daily-mean sunlight at latitude φ and solar declination δ is Q = (S/π)(h₀ sinφ sinδ + cosφ cosδ sin h₀), cos h₀ = −tanφ tanδ. The year average (circular orbit, sinδ = sinε sinλ) integrates over the sphere to exactly S/4 for any tilt ε.
Temperature. Global mean sea-level temperature = effective temperature T_eff = [S(1−A)/4σ]^1/4 (A = 0.30) plus a greenhouse offset. Latitude structure follows annual insolation, T = T_g + 55 K (Q/〈Q〉 − 1). Land cools with height at Γ = 6.5 K/km × g/g₀ (the dry-adiabatic rate is g/c_p, so it follows gravity; exactly 6.5 K/km on Earth).
Rainfall. A zonal profile puts the ITCZ (Hadley ascent) at the thermal equator, which migrates ±0.45ε over the year; the descending branch gives dry subtropics near 30°, with a second wet band (storm tracks) near 55°. Moisture then travels along the prevailing wind (trades <30°, westerlies 30–60°, polar easterlies), decays inland and is wrung out by mountains (orographic lift and rain shadow). Evaporation grows 7 % per kelvin (Clausius–Clapeyron).
Biomes. Each land cell is classified from mean annual temperature and precipitation with simplified Whittaker-diagram boundaries; cold wet cells become ice sheets, cold ocean becomes sea ice.
Sea level & gravity. Ocean fraction is an area-weighted percentile of the elevation field. A mountain column fails when ρ g h ≈ strength, so the tallest relief scales as h_max ∝ 1/g (anchored at 8.85 km for g = 9.81).
Simplifications. No ocean currents, no seasons in temperature, no ice-albedo feedback, no tectonic/erosion physics; the terrain is noise, not geology. Use it for intuition, not prediction.