std.date.toString always returns "... GMT+0000", regardless of the actual timezone. Looking at src/phobos/std/date.d, it looks like the variable 'localTZA' is not initialized, because std_date_static_this() is never called. As a klagde, 'import datebase' calls the function and thus fixes the problem.
*** Issue 3178 has been marked as a duplicate of this issue. ***
http://www.dsource.org/projects/phobos/changeset/2064