WeatherApp - Multi-API Weather Comparison

A comprehensive iOS weather app that aggregates data from multiple sources and presents beautiful, unified visualizations with clear difference highlighting.

Features

• Multi-API Integration: Fetches weather data from:

  • Apple WeatherKit (primary, global)
  • Google Weather (global, optional with API key)
  • NOAA/NWS (free, US-only)
  • OpenWeatherMap (global, optional with API key)
  • Tomorrow.io (global, optional with API key)

• Unified Data Display: Normalizes data from all sources into a consistent domain model

• Forecast Comparison: Side-by-side charts using Swift Charts to visualize differences between sources

• Contextual Search: Search by city name, zip code, "city, state", or coordinates

• Beautiful UI:

  • Gradient backgrounds with animations
  • Frosted glass effects (ultra-thin material)
  • SF Symbols with multicolor rendering
  • Native iOS feel similar to Apple's Weather app

• Smart Caching: 1-hour cache using SwiftData

• Location Services: CoreLocation integration with permission handling

Requirements

• iOS 26.0+
• Xcode 16.0+
• Swift 6.2.1+
• Apple Developer account (for WeatherKit)

Setup

1. WeatherKit Configuration

WeatherKit is already enabled in the project entitlements. Ensure your Apple Developer account has:

• Active Developer Program membership
• WeatherKit enabled for your App ID

2. API Keys (Optional)

To enable additional weather sources, add API keys:

1. Copy .env.example to .env:

   cp .env.example .env

2. Add your API keys to .env:

   # Google Weather API Key (optional)
   # Get from: Google Cloud Console
   GOOGLE_WEATHER_API_KEY=your_key_here
   
   # OpenWeatherMap API Key (optional)
   # Sign up at: https://openweathermap.org/api
   OWM_API_KEY=your_key_here
   
   # Tomorrow.io API Key (optional)
   # Sign up at: https://www.tomorrow.io/weather-api/
   TOMORROW_API_KEY=your_key_here

3. Set environment variables in Xcode:

   • Edit Scheme → Run → Arguments → Environment Variables
   • Add GOOGLE_WEATHER_API_KEY, OWM_API_KEY, and TOMORROW_API_KEY

Note: The app works with just WeatherKit and NOAA. Additional sources are optional.

3. Build and Run

1. Open WeatherApp.xcodeproj in Xcode
2. Select your development team in Signing & Capabilities
3. Build and run on device or simulator

Architecture

MVVM Pattern

Views (SwiftUI)
    ↓
ViewModels (@Observable)
    ↓
WeatherAggregator
    ↓
WeatherServiceProtocol implementations
    → WeatherKitService
    → GoogleWeatherService
    → NOAAWeatherService
    → OpenWeatherMapService
    → TomorrowIOService

Project Structure

Models/
  ├── Domain/          # Unified weather models
  ├── Persistence/     # SwiftData models
  └── API/            # API-specific response models
Services/
  ├── Protocols/      # Service interfaces
  ├── Weather/        # Weather API implementations
  ├── Location/       # Location & geocoding
  └── Network/        # HTTP client
ViewModels/           # Business logic
Views/
  ├── Main/           # Primary screens
  ├── Components/     # Reusable UI
  ├── Search/         # Location search
  └── Comparison/     # Forecast comparison
Utilities/            # Extensions, helpers, constants

Key Components

Domain Models

• WeatherData: Unified weather data from multiple sources
• SourcedWeatherInfo: Weather data from a specific source
• CurrentWeather: Current conditions
• HourlyForecast: Hourly forecast data
• DailyForecast: Daily forecast data
• WeatherCondition: Unified weather condition enum with SF Symbol mappings

Services

• WeatherKitService: Apple WeatherKit integration
• GoogleWeatherService: Google Weather API integration
• NOAAWeatherService: NOAA/NWS API integration
• OpenWeatherMapService: OpenWeatherMap API integration
• TomorrowIOService: Tomorrow.io API integration
• WeatherAggregator: Parallel fetching from all available sources
• GeocodingService: Location search and geocoding
• NetworkClient: HTTP client with retry logic

Views

• ContentView: Main app container
• WeatherMainView: Primary weather display
• LocationSearchView: Search interface
• ForecastComparisonView: Side-by-side comparison
• ComparisonChartView: Overlaid line charts

Testing Locations

• US Location: San Francisco, CA (37.7749, -122.4194) - Tests WeatherKit + NOAA
• International: London, UK (51.5074, -0.1278) - Tests WeatherKit + optional APIs
• Zip Code: 10001 (New York City)
• Coordinates: "40.7128,-74.0060" (NYC)

API Rate Limits

• WeatherKit: 500,000 calls/month (Apple Developer Program)
• Google Weather: Varies by plan (requires Google Cloud account)
• NOAA: No rate limit (free, US-only)
• OpenWeatherMap: 1,000 calls/day (free tier)
• Tomorrow.io: 500 calls/day, 25 calls/hour (free tier)

Known Limitations

• OpenWeatherMap: Hourly forecasts are provided in 3-hour intervals instead of true hourly data. The app displays these as-is without interpolation.

License

This project is a demonstration app. Not for commercial use.

Credits

Weather data provided by:

• Apple WeatherKit
• Google Weather
• NOAA National Weather Service
• OpenWeatherMap
• Tomorrow.io