How to resolve time zone in sharepoint 2013

The below method is used to resolve time zone in sharepoint 2013

public static DateTime ResolveTimeZone(ClientContext oParentContext, DateTime dtDate)
{
   //DateTime dtStartDate = DateTime.UtcNow;
  try
  {
    var spTimeZone = oParentContext.Web.RegionalSettings.TimeZone;
    oParentContext.Load(spTimeZone);
    oParentContext.ExecuteQuery();
    var fixedTimeZoneName = spTimeZone.Description.Replace("and", "&");
    var timeZoneInfo = TimeZoneInfo.GetSystemTimeZones().FirstOrDefault(tz => tz.DisplayName == fixedTimeZoneName); //"(UTC-08:00) Pacific Time (US and Canada)"
    TraceUtil.TraceMessage("UTC= " + dtDate);
    TraceUtil.TraceMessage("TZ= " + timeZoneInfo);
    dtDate = TimeZoneInfo.ConvertTimeFromUtc(dtDate.Date.ToUniversalTime(), timeZoneInfo);
    dtDate = dtDate.Date + ts;
  }
  catch (Exception ex)
  {
     throw ex;
  }

  return dtDate;
}