diff --git a/src/common/datetime.cpp b/src/common/datetime.cpp
index 4aa2d7ce3c..f0d29667ff 100644
--- a/src/common/datetime.cpp
+++ b/src/common/datetime.cpp
@@ -2851,7 +2851,7 @@ const wxChar *wxDateTime::ParseRfc822Date(const wxChar* date)
 
     // the spec was correct, construct the date from the values we found
     Set(day, mon, year, hour, min, sec);
-    MakeFromTimezone(TimeZone(offset*SEC_PER_MIN));
+    MakeFromTimezone(TimeZone((wxDateTime_t)offset*SEC_PER_MIN));
 
     return p;
 }