static String TimeZoneID(double utcTime) {
int tz = (int)(localStandardTZA / msPerHour);
if (DaylightSavingsTime(utcTime + localStandardTZA))
switch (tz){
case -5 : return "EDT";
case -6 : return "CDT";
case -7 : return "MDT";
case -8 : return "PDT";
}
else
switch (tz){
case -5 : return "EST";
case -6 : return "CST";
case -7 : return "MST";
case -8 : return "PST";
}
return (tz >= 0 ? "UTC+" : "UTC") + tz.ToString(CultureInfo.InvariantCulture);
}