diff --git a/do_postgres/ext/do_postgres_ext.c b/do_postgres/ext/do_postgres_ext.c
index e410d53..da6b866 100755
--- a/do_postgres/ext/do_postgres_ext.c
+++ b/do_postgres/ext/do_postgres_ext.c
@@ -118,10 +118,24 @@ static VALUE timezone_to_offset(const char sign, int hour_offset, int minute_off
 	return seconds_to_offset(seconds);
 }
 
+// Culled from Postgres' pgtz.c
+static int get_local_timezone_offset(struct tm * tm) {
+#if defined(HAVE_STRUCT_TM_TM_ZONE)
+	return tm->tm_gmtoff;
+#else
+#ifndef __CYGWIN__
+	return -timezone;
+#else
+	return -_timezone;
+#endif
+#endif
+}
+
 static VALUE parse_date_time(const char *date) {
 	VALUE ajd, offset;
 
 	int year, month, day, hour, min, sec, usec, hour_offset, minute_offset;
+	int gmt_offset;
 	int jd;
 	char sign;
 	do_int64 num, den;
@@ -155,9 +169,12 @@ static VALUE parse_date_time(const char *date) {
 			
 		// TODO: Refactor the following few lines to do the calculation with the *seconds*
 		// value instead of having to do the hour/minute math
-		hour_offset = abs(timeinfo->tm_gmtoff) / 3600;
-		minute_offset = abs(timeinfo->tm_gmtoff) % 3600 / 60;
-		sign = timeinfo->tm_gmtoff < 0 ? '-' : '+';
+		
+		gmt_offset = get_local_timezone_offset(timeinfo);
+		
+		hour_offset = abs(gmt_offset) / 3600;
+		minute_offset = abs(gmt_offset) % 3600 / 60;
+		sign = gmt_offset < 0 ? '-' : '+';
 	} else {
 		// Something went terribly wrong
 		rb_raise(ePostgresError, "Couldn't parse date: %s", date);