Global Climate Diagrams
Every place on Earth has a climate you can summarise in a single picture: how warm it is each month, and how much rain falls. Putting those two curves on one chart results in a climate diagram (or a Walter–Lieth diagram, after the two ecologists who standardised it). Click anywhere on the map below and one will be drawn for that spot.
Explore
Click the map, pick a biome from the menu, or type coordinates. The link in your browser’s address bar updates as you go, so you can copy it to share or hand in a specific location.
Things to try
- Compare Manaus and Darwin. Both are tropical and both are hot all year — so why is one rainforest and the other savanna? Look at the dry season.
- Find Nairobi. It sits almost exactly on the equator, but it is not hot. Check the elevation in the diagram header.
- Click somewhere in the Andes, then somewhere in Kansas. Notice which diagram warns you that the grid cell is hiding a lot of terrain, and think about what that means for how much you should trust it.
- Walk north up a single line of longitude — say 100° W — from Mexico to the Arctic, clicking every few degrees. Watch the temperature curve flatten out and drop.
How to read a climate diagram
Two lines, two axes. The red line is temperature, read against the axis on the left in °C. The blue line is rainfall, read against the axis on the right in mm. Each point is an average for that month.
The two axes are deliberately linked. 10 °C on the left lines up with 20 mm on the right. That is not an accident — it is the whole trick of the diagram. Where the rainfall line sits above the temperature line, more water arrives than the warmth can evaporate, and plants have water to work with: a wet season (blue hatching). Where rainfall drops below temperature, it is a dry season (orange dots). You can spot a Mediterranean summer drought or a monsoon instantly, without reading a single number.
The right-hand axis changes scale at 100 mm. Below 100 mm each 10 °C is 20 mm; above it, each 10 °C is 200 mm. Without that squeeze, a wet tropical month would run off the top of the page. The chart marks where the change happens — watch for it, because it makes very wet months look flatter than they are.
A note on months. Southern-hemisphere diagrams start in July, so that summer sits in the middle of the chart just as it does for northern ones. The chart says so when it does this.
About the data
Monthly averages come from WorldClim 2.1, which describes the climate of 1970–2000 — a 30-year average, not this year’s weather, and not a forecast. Values are given for grid cells 0.5° across (roughly 55 km north–south), so each diagram describes a region, not a point. In mountainous or coastal places the real climate can vary sharply inside one cell, and the diagram says so when the terrain warrants it.
Fick, S.E. and R.J. Hijmans (2017). WorldClim 2: new 1 km spatial resolution climate surfaces for global land areas. International Journal of Climatology 37(12): 4302–4315.
Basemap: Natural Earth II (public domain). Map interaction by Leaflet.