GetAirQualityInformation.cs

using OpenMeteo;

OpenMeteoClient client = new();
try
{
    if (await client.QueryAsync("Menziken", new() { Current = CurrentOptions.All, Daily = DailyOptions.All }) is WeatherForecast weatherForecast)
    {
        Console.WriteLine($"found Menziken at {weatherForecast.Latitude} & {weatherForecast.Longitude}");
        Console.WriteLine();

        var airQuality = await client.QueryAsync(new AirQualityOptions(weatherForecast.Latitude, weatherForecast.Longitude, AirQualityOptions.HourlyOptions.All, "auto", "iso8601", "auto", 0, DateTime.Today.ToString("O"), DateTime.Today.ToString("O")));

        if (airQuality?.Hourly?.Birch_pollen?.Where(p => p != null).Cast<float>().ToArray() is float[] pollen)
        {
            var daily = GroupDaily(pollen);
            var unit = airQuality.Hourly_Units?.Birch_pollen ?? "";
            foreach(var day in daily)
            {
                Console.WriteLine($"day: {day.Day.ToLongDateString()}");
                Console.WriteLine($"samples: {day.Samples.Length} from {day.StartHour}:00 to {day.EndHour}:00");
                var min = day.Samples.Index().MinBy(v => v.Item);
                var max = day.Samples.Index().MaxBy(v => v.Item);
                Console.WriteLine($"min: {min.Item} {unit} @ {day.StartHour + min.Index}:00");
                Console.WriteLine($"max: {max.Item} {unit} @ {day.StartHour + max.Index}:00");
                Console.WriteLine();
            }
        }
    }
} catch(Exception e)
{
    Console.WriteLine(e.ToString());
}

static IEnumerable<DailySamples> GroupDaily(float[] data)
{
    var start = DateTime.Now.Hour;

    var index = 0;

    if(start != 24)
    {
        yield return new DailySamples(DateTime.Today, start, 24, data[start..24]);
        index++;
    }

    foreach(var chunk in data[(24 * index)..].Chunk(24))
    {
        yield return new DailySamples(DateTime.Today.AddDays(index), 0, chunk.Length, chunk);
        index++;
    }
}

record DailySamples(DateTime Day, int StartHour, int EndHour, float[] Samples);