diff --git a/code/__DEFINES/time.dm b/code/__DEFINES/time.dm
index c67e8e60065..9600b2f5c2e 100644
--- a/code/__DEFINES/time.dm
+++ b/code/__DEFINES/time.dm
@@ -117,9 +117,15 @@ When using time2text(), please use "DDD" to find the weekday. Refrain from using
 /// Eastern Daylight Time
 #define TIMEZONE_EDT -4
 
+/// Eastern Standard Time
+#define TIMEZONE_EST -5
+
 /// Central Daylight Time
 #define TIMEZONE_CDT -5
 
+/// Central Standard Time
+#define TIMEZONE_CST -6
+
 /// Mountain Daylight Time
 #define TIMEZONE_MDT -6
 
@@ -129,9 +135,15 @@ When using time2text(), please use "DDD" to find the weekday. Refrain from using
 /// Pacific Daylight Time
 #define TIMEZONE_PDT -7
 
+/// Pacific Standard Time
+#define TIMEZONE_PST -8
+
 /// Alaska Daylight Time
 #define TIMEZONE_AKDT -8
 
+/// Alaska Standard Time
+#define TIMEZONE_AKST -9
+
 /// Hawaii-Aleutian Daylight Time
 #define TIMEZONE_HDT -9
 
diff --git a/code/modules/holiday/nth_week.dm b/code/modules/holiday/nth_week.dm
index 10ecc11b3ca..d18b9e8baf2 100644
--- a/code/modules/holiday/nth_week.dm
+++ b/code/modules/holiday/nth_week.dm
@@ -31,6 +31,7 @@
 
 /datum/holiday/nth_week/thanksgiving
 	name = "Thanksgiving in the United States"
+	timezones = list(TIMEZONE_EST, TIMEZONE_CST, TIMEZONE_MST, TIMEZONE_PST, TIMEZONE_AKST, TIMEZONE_HST)
 	begin_week = 4
 	begin_month = NOVEMBER
 	begin_weekday = THURSDAY