Retrieving the actual forecast

We have almost completed the app, but it is still missing the most important part—the weather forecast.

Getting the forecast from OpenWeatherMap

There are a plenty of services that provide forecast for free or for a small amount of money.

For our app, we'll use http://openweathermap.org, whose API is free for a small number of calls.

First of all, we create the struct to handle the forecast:

import Foundation
struct WeatherCondition {
    let cityName: String?
    let weather: String
    let icon: IconType?
    let time: NSDate
    let tempKelvin: Double
    let maxTempKelvin: Double
    let minTempKelvin: Double
    
    var tempFahrenheit: Double {
        get {
            return tempCelsius * 9.0/5.0 + 32.0
        }
    }
    
    var maxTempFahrenheit: Double {
        get {
            return maxTempCelsius * 9.0/5.0 + 32.0
        }
    }
    var minTempFahrenheit: Double {
        get {
            return minTempCelsius * 9.0/5.0 + 32.0
        }
    }...