What is Annular?
Annular is a climate visualization tool that displays a full year of weather history for any location on Earth. Search for a city, click the globe, and see daylight hours, temperature, and precipitation rendered as concentric rings — one slice per month.
Data sources
Weather history
Open-Meteo Archive API — daily temperature & precipitation going back to 1940
Geocoding
Nominatim (OpenStreetMap) — location search and reverse geocoding from globe clicks
Daylight hours
Calculated locally using an astronomical formula based on latitude and day of year
Globe geometry
Natural Earth via world-atlas — country outlines and graticule
Tech stack
Rendering
D3 v7 — globe projection, radial area paths, transitions
Map data
TopoJSON v3 + world-atlas@2
Typography
Space Mono (Google Fonts)
Architecture
Single HTML file — no build step, no dependencies to install
Hosting
Vercel — auto-deploys from GitHub on push to main
Local storage
Recent searches, weather cache (7-day TTL), popular places, and visitor sessions are stored in your browser only