diff --git a/zones.csv b/zones.csv
index b6a598c..93d86c8 100644
--- a/zones.csv
+++ b/zones.csv
@@ -92,7 +92,7 @@
 "America/Cuiaba","<-04>4"
 "America/Curacao","AST4"
 "America/Danmarkshavn","GMT0"
-"America/Dawson","PST8PDT,M3.2.0,M11.1.0"
+"America/Dawson","MST7"
 "America/Dawson_Creek","MST7"
 "America/Denver","MST7MDT,M3.2.0,M11.1.0"
 "America/Detroit","EST5EDT,M3.2.0,M11.1.0"
@@ -194,7 +194,7 @@
 "America/Toronto","EST5EDT,M3.2.0,M11.1.0"
 "America/Tortola","AST4"
 "America/Vancouver","PST8PDT,M3.2.0,M11.1.0"
-"America/Whitehorse","PST8PDT,M3.2.0,M11.1.0"
+"America/Whitehorse","MST7"
 "America/Winnipeg","CST6CDT,M3.2.0,M11.1.0"
 "America/Yakutat","AKST9AKDT,M3.2.0,M11.1.0"
 "America/Yellowknife","MST7MDT,M3.2.0,M11.1.0"
diff --git a/zones.json b/zones.json
index 705926d..78396be 100644
--- a/zones.json
+++ b/zones.json
@@ -93,7 +93,7 @@
 "America/Cuiaba":"<-04>4",
 "America/Curacao":"AST4",
 "America/Danmarkshavn":"GMT0",
-"America/Dawson":"PST8PDT,M3.2.0,M11.1.0",
+"America/Dawson":"MST7",
 "America/Dawson_Creek":"MST7",
 "America/Denver":"MST7MDT,M3.2.0,M11.1.0",
 "America/Detroit":"EST5EDT,M3.2.0,M11.1.0",
@@ -195,7 +195,7 @@
 "America/Toronto":"EST5EDT,M3.2.0,M11.1.0",
 "America/Tortola":"AST4",
 "America/Vancouver":"PST8PDT,M3.2.0,M11.1.0",
-"America/Whitehorse":"PST8PDT,M3.2.0,M11.1.0",
+"America/Whitehorse":"MST7",
 "America/Winnipeg":"CST6CDT,M3.2.0,M11.1.0",
 "America/Yakutat":"AKST9AKDT,M3.2.0,M11.1.0",
 "America/Yellowknife":"MST7MDT,M3.2.0,M11.1.0",