WeatherKit

Fetch current conditions, hourly and daily forecasts, weather alerts, and historical statistics using WeatherService. Displays mandatory Apple Weather attribution.

Contents

• Setup & Permissions
• Fetching Weather Data
• Selective Queries
• Context & Historical Queries (iOS 18+)
• Attribution Requirements
• Caching & Rate Limits
• Common Mistakes
• Review Checklist
• References

Setup & Permissions

1. Enable the WeatherKit capability in Xcode.
2. Enable WeatherKit for your App ID in the Apple Developer portal.
3. Add NSLocationWhenInUseUsageDescription to Info.plist if requesting coordinates via CoreLocation.
4. Use WeatherService.shared across the app.

Fetching Weather Data

Fetch complete weather datasets for a target CLLocation:

import WeatherKit
import CoreLocation

let weather = try await WeatherService.shared.weather(for: location)

// Current conditions
let current = weather.currentWeather
print("Temperature: \(current.temperature.formatted())")
print("Condition: \(current.condition.description), SF Symbol: \(current.symbolName)")

// Hourly and Daily forecasts
for hour in weather.hourlyForecast.prefix(12) {
    print("\(hour.date.formatted(date: .omitted, time: .shortened)): \(hour.temperature.formatted())")
}

Format Measurement<UnitTemperature> values with .formatted() to honor user locale conventions.

Selective Queries

Reduce bandwidth and processing by requesting only necessary datasets:

let (current, hourly) = try await WeatherService.shared.weather(
    for: location,
    including: .current, .hourly
)

Available query types include .current, .hourly, .daily, .minute, and .alerts.

Context & Historical Queries (iOS 18+)

Access climate context, historical comparisons, and weather summaries:

// Query weather changes (e.g. temperature shift since yesterday)
let changes = try await WeatherService.shared.weather(for: location, including: .changes)

// Historical comparison
let historical = try await WeatherService.shared.weather(for: location, including: .historicalComparisons)

Attribution Requirements

Apple requires visible attribution whenever WeatherKit data is displayed:

let attribution = try await WeatherService.shared.attribution
// Display attribution.combinedMark (light/dark Apple Weather logo)
// Provide tappable link to attribution.legalPageURL

In SwiftUI, display attribution using Link and the official logo asset.

Caching & Rate Limits

• Respect metadata.expirationDate returned with forecasts; avoid refetching unexpired data.
• Batch requests by coordinates and debounce location updates to stay within API tier allowances.

Common Mistakes

• Omitting mandatory Apple Weather attribution: App Store review rejects apps displaying WeatherKit data without legal attribution and logo.
• Ignoring forecast expiration dates: Calling weather(for:) on every view appearance causes rate-limiting errors. Respect metadata.expirationDate.
• Hardcoding temperature unit conversion: Manually calculating Fahrenheit/Celsius ignores system locale. Use temperature.formatted().
• Requesting all datasets when only current weather is needed: Increases network latency. Use selective including: queries.
• Missing Apple Developer WeatherKit entitlement: WeatherKit calls fail if the capability is not enabled in the developer portal.

Review Checklist

• WeatherKit capability enabled in Xcode and Developer Portal
• Required Apple Weather attribution logo and legal link displayed
• Temperatures formatted via Measurement.formatted()
• Selective queries (including:) used to minimize network payload
• Forecasts cached and refreshed according to metadata.expirationDate

References

• Extended patterns (SwiftUI dashboard, charts integration, historical statistics): references/weatherkit-patterns.md
• WeatherKit framework
• WeatherService
• WeatherAttribution
• WeatherQuery
• WeatherQuery.daily(startDate:endDate:)
• WeatherQuery.hourly(startDate:endDate:)
• CurrentWeather
• CurrentWeather.temperature
• Measurement.formatted()
• Forecast
• HourWeather
• DayWeather
• WeatherAlert
• WeatherAvailability
• WeatherMetadata.expirationDate
• WeatherQuery.changes
• WeatherQuery.historicalComparisons
• WeatherKit updates
• Bring context to today's weather
• WeatherService.weather(for:)