Show HN: I built a weather alert system for photographers

4 points by pontussw 8 months ago · 2 comments · 2 min read

I kept missing the good stuff (fog, aurora, beautiful sunsets) because I wasn't checking forecasts at the right time, so I built PhotoWeather...

You define rules like: `aurora_quality > 60 AND cloud_cover < 20% AND moon_below_horizon` `fog_prob > 70% AND within 30min of sunrise AND wind < 5 mph`

When a rule matches, you get an email and/or an iCal event. The iCal feed is the part I am maybe most proud of: subscribe once and upcoming "shoot windows" show up in your calendar.

One example that made me sure this wasn't just a toy: last October it alerted "clear skies + no moon + strong aurora" and I drove to a nearby high spot in Helsinki. Ended up catching aurora and Comet C/2025 A6 (Lemmon) in one frame: https://reddit.com/r/Finland/comments/1obc5nz/

Not my best photo ever, but probably the most unique and memorable, and I'll continue to remember my real-life "photoweather actually works" moment through it.

A few things that differentiates this from your average weather app:

Spatial sampling A single forecast coordinate often isn't representative of what you'll actually see. So for many scores I sample 24 points around the location (8 directions × 3 distances). Rainbow probability is a good example – it checks for rain in the antisolar direction and clear sky toward the sun.

Derived scores Photography-specific scores like fog probability use actual meteorology: dewpoint spread, vapor pressure deficit, with guard clauses (wind >6m/s disperses fog, so score drops to zero).

Data / stack Open-Meteo as the primary model; GFS for multi-point sampling and cross-checks; GEFS for ensemble clouds; GFS Wave for sea conditions; NOAA OVATION + SWPC/Kp for aurora; CAMS aerosols. FastAPI + Postgres + Celery/Redis + React/TypeScript.

Free tier is usable but tuned for low running cost; paid unlocks mainly more locations and rules, more specialized weather data and faster refreshes.

Landing page: https://photoweather.app | Demo dashboard: https://app.photoweather.app/demo/live-demo

Would love to hear feedback, especially things like:

Would you actually use this? Does the UI/UX make sense (I feel a bit blinded by building+being a user at the same time)? Is there anything that would make it more useful/usable for you?