You could use the Time::Piece module which has been in the core Perl distribution since 5.10 I believe.

johngg@shiraz:~/perl/Monks$ perl -Mstrict -Mwarnings -MTime::Piece -E 
+'
my $now = localtime();
my $may = Time::Piece->strptime( qq{@{ [ $now->year() ] }/05/01 00:00:
+00}, q{%Y/%m/%d %T} );
say
   $now->epoch() < $may->epoch()
   ? q{Before 1st May}
   : q{After 1st May};'
After 1st May
[download]

I hope this is helpful.

Update:The "false" part of the ternary would more accurately say "On or after 1st May" being pedantic.