City Clusters

Colour is hotness against each city's own normal, in standard deviations — the only form comparable across cities. +3 °C is a warm afternoon in Chicago and a once-in-years event in Beirut, so degrees alone would rank cities by how continental their climate is. The ring is the region, size is 24h traded volume, and a pulsing ring means the peak window is open there right now. Baseline is every year's observations within ten days of today's date; a city without enough history shows grey and says so.