wttr.in is a production-grade weather forecast service accessible via HTTP, designed primarily for terminal use with `curl`. It provides weather reports in multiple formats: ANSI-colored text (v1 and v2 views), plain text, JSON (j1/j2), Prometheus metrics (p1), HTML, and PNG images. The service automatically detects the user's location via IP geolocation (MaxMind GeoIP2) or explicit city/airport/coordinate queries, then fetches weather data from WorldWeatherOnline (the only actively configured data source). The architecture is a single Go binary with embedded assets (fonts, translations, templates) and a pipeline of interfaces: query parsing, location resolution, weather fetching, caching, rendering, and formatting. It supports 74 languages with per-language translation files and a rule-based routing system for selecting views and output types. The codebase demonstrates solid engineering with interface-based design, multiple caching layers (LRU in-memory, disk-based, SQLite-backed location cache), and request coalescing to prevent thundering herd on upstream APIs. However, it shows signs of technical drift: reliance on a single external weather API, hardcoded paths in configuration, disabled linters, and incomplete translations. The project is actively maintained with a large user base and extensive integration documentation for tools like tmux, Waybar, Emacs, and Google Sheets.