.NET timer imprecise?

I am developing an application and I need to get the current date from the server (it is different from the machine date). I am getting the date from the server and with a simple Split I create a new DateTime:

globalVars.fec = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, int.Parse(infoHour[0]), int.Parse(infoHour[1]), int.Parse(infoHour[2]));

      

        
        
        
      

    

globalVars is a class and fec is a public static variable, so I can access it anywhere in the application (bad coding I know ...). Now I need to set a timer if this date is equal to some of the dates I have stored in the list, and if it is, I just call the function.

List<DateTime> fechas = new List<DateTime>();

      

        
        
        
      

    

Before getting the date from the server, I was using the computer's date, so to check if the dates match, I used this:

private void timerDatesMatch_Tick(object sender, EventArgs e)
{
    DateTime tick = DateTime.Now;
    foreach (DateTime dt in fechas)
    {
        if (dt == tick)
        {
            //blahblah
        }
    }
}

      

        
        
        
      

    

Now I have a date from the server, so DateTime.Now cannot be used here. Instead, I created a new timer with Interval = 1000 and per tick. I am adding 1 second to globalVars.fec using:

globalVars.fec = globalVars.fec.AddSeconds(1);

      

        
        
        
      

    

But the watch is not accurate, and every 30 minutes the watch loses about 30 seconds.

Is there any other way to do what I am trying to do? I thought about using threading.timer, but I need to be able to access other threads and non-static functions.