diff --git a/src/lib/units/offset.js b/src/lib/units/offset.js
index f81b096b63..168aeadd80 100644
--- a/src/lib/units/offset.js
+++ b/src/lib/units/offset.js
@@ -171,7 +171,7 @@ export function setOffsetToLocal (keepLocalTime) {
 }
 
 export function setOffsetToParsedOffset () {
-    if (this._tzm) {
+    if (this._tzm != null) {
         this.utcOffset(this._tzm);
     } else if (typeof this._i === 'string') {
         var tZone = offsetFromString(matchOffset, this._i);