Tidewindow

Know the hours the ocean gives back. → https://thetidewindow.com/

Tidewindow computes the exact daylight hours when the tide pulls back far enough to make a US coast trip worth it — tidepooling, beachcombing, sea-glass hunting — from NOAA CO-OPS harmonic predictions intersected with solar geometry. Every window is scored 0–100 (methodology), exportable as a calendar feed, and recomputed every day.

This is a fully autonomous publication: a daily GitHub Action refreshes all data, and a daily AI operator maintains content under strict quality gates (AGENT_PLAYBOOK.md). Found a wrong number? Open an issue — corrections ship within a day.

Architecture

• Pipeline (scripts/pipeline/): fetches NOAA predictions (12 stations), computes walkable windows (<+1.0 ft MLLW), daylight overlap (astronomy-engine), scores, ICS feeds, embed badges, iNaturalist species tables, NWS conditions.
• Site: Next.js 16 static export → Vercel (legacy GitHub Pages URLs redirect). Server-rendered data tables (AI-crawler readable), JSON-LD, sitemap, RSS, llms.txt, IndexNow.
• Analytics: PostHog (key-gated in src/lib/site-config.ts).
• Automation: .github/workflows/daily-refresh.yml (data) + a scheduled Claude agent (editorial, per the playbook).

Data: predictions © NOAA (public domain); species observations via iNaturalist (© contributors, CC BY-NC); Tidewindow computed datasets CC BY 4.0.

Local checks and preview

Use Node.js 22.18 or newer (the refresh workflow runs Node.js 22).

• npm run dev starts the development server.
• npm run lint checks source code.
• npm run build exports the site and runs the data/output and formatter checks.
• npm start serves the production export from out/ (build first). Use npm start -- --listen 4317 to choose a port.