Build a weather app with forecasts and alerts (no code)

Weather apps are a classic first project because they combine a real API, a nice UI and a reason to open the app every day. Farmers, fishermen, event planners and commuters all want a specific view of the weather — rain probability by hour, wind for the coast, a frost warning — that generic apps bury.

This guide builds a weather app with a free forecast API, city search, hourly and daily views, and alerts, and shows how to phrase the API details so the agent wires it correctly.

What a weather app should show

Pick the views your users care about; a fisherman’s app and a farmer’s app are not the same app:

• Current conditions — Temperature, feels-like, humidity, wind, an icon and a one-line summary.
• Hourly for the next 24 hours — Temperature and rain probability as a scrollable strip.
• 7-day forecast — Highs, lows, rain, and an icon per day.
• Locations — GPS for “here”, a search box for cities, saved favourites.
• Alerts — Rain in the next hour, frost tonight, wind above a threshold — as notifications.
• Units and language — °C/°F, km/h vs m/s, local names for weather words.
• Offline last-known — Show the last fetched forecast when there is no network, with a timestamp.

Build it with App Builder Agent, step by step

Name a free API so no key is needed — Open-Meteo is the usual choice — and the agent handles the rest.

1. Create a mobile app project. GPS and notifications want a native app; a website version works for a dashboard.
2. Describe the views and name the API. Say which data you want and where from.
   Build a weather app called Sky for Bangladesh. Use the free Open-Meteo API (no key). Home: current temperature, feels-like, humidity, wind, rain probability, with a background that changes by weather. Hourly strip for 24 hours. 7-day list. Location by GPS and a city search using Open-Meteo geocoding; favourites list. Units °C/km/h. Bengali and English. Cache the last forecast for offline.
3. Check a real city in the simulator. Compare with any weather site. If something looks wrong, tell the agent which field.
4. Add alerts. Rain in the next hour and heat/frost warnings as local notifications.
   Add alerts: notify me when rain probability in the next 2 hours exceeds 60%, and a morning summary at 7 am for my favourite location.
5. Install. Export the APK. Weather apps are also excellent websites — publish the project for a link people can bookmark.

Prompts that work well

Specialised weather apps people actually want:

Make it feel finished

• Cache the last response and show its time — networks drop, apps should not go blank.
• Use rain probability, not just an icon; people plan around it.
• Ask for a background that changes with conditions; it makes the app feel alive.
• Keep GPS optional: a city search must work without location permission.

API keys and hosting

Open-Meteo needs no key, so the app talks to it directly and there is nothing to host. If you use a keyed provider, ask the agent for a settings screen where the key is entered on the device, or for a small hosted backend that keeps the key server-side — the platform hosts it with the project.

Publish the website version too: a weather page for your town is easy search traffic.

Frequently asked