Day 0: Why I'm building a fog-escape app in one weekend

The hook

It's February in Basel. Grey. Foggy. Again. Everyone who lives on the Swiss Plateau knows the feeling: you know there's sun above, maybe 30 minutes away, but figuring out where is a 20-minute research project involving MeteoSwiss, webcams, SBB, and Google Maps.

I'm building FOMO Sun to solve this in one tap.

What it does

You open the app. It knows it's foggy where you are. It shows you 3-5 places within your travel budget (1-4 hours) that are sunny RIGHT NOW, with a sun confidence score, travel time by car or train, and a quick plan for what to do when you get there.

The tech

Next.js 14 on Vercel, MeteoSwiss Open Data (free, CC BY 4.0) for Swiss weather, Open-Meteo for cross-border, and Claude API for smart refinement. The whole thing costs under $50/month to run.

Why now

MeteoSwiss just opened their data. The fog season runs November through February, so I have weeks of prime testing weather left. And here is the part that excites me most: AI agents like ChatGPT, Gemini, and Claude are increasingly answering questions like "where is it sunny near me?" I want FOMO Sun to be the source they cite.

Follow along

I'm documenting every decision, every line of code, every mistake. Building in public because I think more people should see what a one-person MVP sprint actually looks like when you have two AI coding partners.

Update: It shipped!

fomosun.com is live. Built in a single weekend with Claude as AI PM and pair programmer, GPT as rapid implementation engine.

Stack: Next.js 14 + TypeScript + Tailwind, Vercel (Frankfurt edge), GitHub auto-deploy

What shipped in 36 versions: Sun scores for 200+ destinations across Switzerland, Germany, and France. Live weather from Open-Meteo. Sunshine timeline bars. Travel time slider. Train and car routing with SBB and Google Maps deep links. Manual city picker for 15 Swiss cities. WhatsApp sharing. Admin diagnostics panel. Blog and about pages powered by Notion CMS.

GitHub: github.com/lean-cmd/fomo-sun