Lat 0°Elev 0 mKoppen ——Day 0 · T 0 °C · P 0 mmFPS 0

Drag to orbit, wheel or pinch to zoom, click the land to move the station. Equator at the middle, poles at the ends; the sea is on the near side, the dry interior far away. Relief is drawn at one quarter of its true height. Colours are the Koppen climate classes computed for every point from latitude, elevation and distance from the sea.

Climate Station: Latitude, Elevation and Distance from the Sea Set the Koppen Climate

Move a weather station over an idealised continent and read its twelve-month climograph. Which climate does it have, and why?

Station

Override the elevation (put the station on a balloon or a mountain)

Climate change and season

Live readouts

Climograph (bars: precipitation, line: temperature)

Insolation against latitude (W/m², top of atmosphere)

Climate along the meridian at this distance from the sea

Upper strip: at sea level. Lower strip: at the real terrain height of this slice. The white tick is the station.

Missions

Predict: at 2° latitude, how high (m) must you climb before the climate stops being tropical (coldest month under 18 °C)?

Hint: temperature falls about 6.5 °C per kilometre of height.

Experiments

Each button changes one variable at the station and reports the climate each time.

Independent numerical checks

Legend: Koppen classes

Controls

Drag / one finger: orbit; wheel / pinch: zoom; click or tap the land to move the station.
Latitude and distance from the sea move the station; its elevation follows the terrain unless you override it.
The warming slider adds a uniform temperature rise to every point; the map recolours at once.
Play the year to step through the seasons: the sun declination, day length and the highlighted month move together.

The science

Insolation. The daily-mean sunlight at the top of the atmosphere is Q = (S/π)(d₀/d)² (h₀ sinφ sinδ + cosφ cosδ sin h₀) with S = 1361 W/m², latitude φ, solar declination δ = asin(sin 23.44° sin(2π(d-80)/365.25)) and the sunset hour angle cos h₀ = -tanφ tanδ (h₀ = 0 in polar night, π in polar day). Averaged over the sphere and the year it is S/4 = 340 W/m²; at the pole on the June solstice it is larger than at the equator, but the sun is low and the ground cold, so it does not make a hot pole.

Temperature. The annual mean at sea level uses an illustrative fit T = -20 + 47.5 cos^1.2φ (°C), lapse rate 6.5 °C per km, plus your warming. The seasonal cycle follows the insolation with a lag of about one month and an amplitude that grows with distance from the sea (coastal 0.03, interior 0.09 °C per W/m²) and shrinks near the poles. These coefficients are not fitted to data: they make a believable idealised world.

Precipitation. A tropical rain belt that follows the sun (the ITCZ moves about 7° each way with a month's delay), dry subtropics near 28°, storm-track rain near 50°, drier interiors, a mild gain with height, and winter-wet or summer-wet seasonality that depends on latitude and distance from the sea. Parametric, invented for teaching.

Koppen-Geiger. The classification follows Peel et al. (2007): E if the warmest month is under 10 °C; B if annual rain is under 10 × a threshold (2T, 2T+14 or 2T+28 mm depending on when the rain falls; BW below half of it, h or k by 18 °C mean); A if the coldest month is 18 °C or more (Af if the driest month has at least 60 mm, Am, Aw); otherwise C (coldest month above -3 °C) or D, with s, w, f for the dry season and a, b, c, d for summer warmth. The checks run it on nine published station normals.

Simplifications. One idealised continent, no ocean currents, no winds, no rain-shadow modelling beyond a drier interior, no clouds or albedo feedback, relief shown at a quarter of its true height. This is not a climate model; do not read forecasts from it. Assets built with Blender; scene by Three.js.