Get local time based on coordinates

You can do it using Google api for identifying current timezone.
.Net Fiddle example:

public class Program
{
    public static DateTime GetLocalDateTime(double latitude, double longitude, DateTime utcDate)
    {
        var client = new RestClient("https://maps.googleapis.com");
        var request = new RestRequest("maps/api/timezone/json", Method.GET);
        request.AddParameter("location", latitude + "," + longitude);
        request.AddParameter("timestamp", utcDate.ToTimestamp());
        request.AddParameter("sensor", "false");
        var response = client.Execute<GoogleTimeZone>(request);

        return utcDate.AddSeconds(response.Data.rawOffset + response.Data.dstOffset);
    }

    public static void Main()
    {
        var myDateTime = GetLocalDateTime(33.8323, -117.8803, DateTime.UtcNow);
        Console.WriteLine(myDateTime.ToString());
    }
}

public class GoogleTimeZone 
{
    public double dstOffset { get; set; }
    public double rawOffset { get; set; }
    public string status { get; set; }
    public string timeZoneId { get; set; }
    public string timeZoneName { get; set; }
}

public static class ExtensionMethods 
{
    public static double ToTimestamp(this DateTime date)
    {
        DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);
        TimeSpan diff = date.ToUniversalTime() - origin;
        return Math.Floor(diff.TotalSeconds);
    }
}

And then you can easily use your GetLocalDateTime(double latitude, double longitude, DateTime utcDate) method as it was shown in the example above:

public static void Main()
{
    var myDateTime = GetLocalDateTime(33.8323, -117.8803, DateTime.UtcNow);
    Console.WriteLine(myDateTime.ToString());
}

Here's my solution. It works offline (so no call to an api). It's fast and the packages are widely used and available on Nuget.

string tzIana = TimeZoneLookup.GetTimeZone(lat, lng).Result;
TimeZoneInfo tzInfo = TZConvert.GetTimeZoneInfo(tzIana);
DateTimeOffset convertedTime = TimeZoneInfo.ConvertTime(DateTimeOffset.UtcNow, tzInfo);