WPF DataTemplate DataTrigger

<Window x:Class="WpfApp79.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp79"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <local:GeneralForecastToBrushConverter x:Key="gf2brush"/>
    </Window.Resources>
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition />
        </Grid.RowDefinitions>
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Select number of days to forecast:"
                       FontSize="15" VerticalAlignment="Center" Margin="4"/>
            <ComboBox x:Name="_days" SelectedIndex="0" Width="50"/>
            <Button Margin="4" Content="Get Forecast" FontSize="16" Click="Button_Click" />
        </StackPanel>
        <StackPanel Orientation="Horizontal" Grid.Row="1" Margin="5"
                    TextBlock.FontSize="15">
            <TextBlock Text="Select units:" Margin="4"/>
            <RadioButton Content="Celsius" IsChecked="True"
                         Margin="10,5"/>
            <RadioButton Content="Fahrenheit" Margin="20,5"/>
        </StackPanel>
        <ListBox ItemsSource="{Binding}" Grid.Row="2" 
                 HorizontalContentAlignment="Stretch">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <Border x:Name="_border" Margin="5" BorderBrush="Black" Padding="5"
                            BorderThickness="2"  
                            Background="LightGray">
                        <StackPanel Orientation="Horizontal">
                            <TextBlock FontSize="20" FontWeight="ExtraBold"
                                       Text="{Binding GeneralForeCastValue}" 
                                       Background="{Binding GeneralForecast,Converter={StaticResource gf2brush}}"/>
                            <TextBlock FontSize="16" Margin="10,0,0,0"
                                       VerticalAlignment="Bottom"
                                       Text="{Binding TemperatureLow,StringFormat='Low:\{0:N2\}'}"/>
                            <TextBlock FontSize="16" Margin="10,0,0,0"
                                       VerticalAlignment="Bottom"
                                       Text="{Binding TemperatureHigh,StringFormat='High:\{0:N2\}'}"/>
                            <TextBlock FontSize="16" Margin="20,0,0,0"
                                       VerticalAlignment="Bottom"
                                       Text="{Binding Percipitation,StringFormat='Percip:\{0:N2\}'}"/>
                        </StackPanel>
                    </Border>
                    <DataTemplate.Triggers>
                        <DataTrigger Binding="{Binding GeneralForeCastValue}" Value="Sunny">
                            <Setter Property="Background" Value="Yellow" TargetName="_border"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding GeneralForeCastValue}" Value="Snowy">
                            <Setter Property="Background" Value="LightBlue" TargetName="_border"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding GeneralForeCastValue}" Value="Rainy">
                            <Setter Property="Background" Value="LightGreen" TargetName="_border"/>
                        </DataTrigger>
                        <DataTrigger Binding="{Binding GeneralForeCastValue}" Value="Dry">
                            <Setter Property="Background" Value="LightYellow" TargetName="_border"/>
                        </DataTrigger>
                    </DataTemplate.Triggers>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </Grid>
</Window>


using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApp79
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            _days.ItemsSource = Enumerable.Range(1, 30);
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            var data = new List<Forecast>();
            int days = (int)_days.SelectedItem;
            var rnd = new Random();
            for (int i = 0; i < days; i++)
            {
                double temp = rnd.NextDouble() * 40 - 10;
                var forecast = new Forecast
                {
                    GeneralForeCastValue = (GeneralForecast)rnd.Next(Enum.GetValues(typeof(GeneralForecast)).Length),
                    TemperatureLow = temp,
                    TemperatureHigh = temp + rnd.NextDouble() * 15,
                    Percipitation = rnd.Next(10) > 5 ? rnd.NextDouble() * 10 : 0
                };
                data.Add(forecast);
            }
            DataContext = data;

        }
    }

    public class Forecast
    {
        public GeneralForecast GeneralForeCastValue { get; set; }
        public double TemperatureHigh { get; set; }
        public double TemperatureLow { get; set; }
        public double Percipitation { get; set; }
    }

    public enum GeneralForecast
    {
        Sunny,
        Rainy,
        Snowy,
        Cloudy,
        Dry
    } 
}