diff --git a/t/pt-tcp-model/analyses.t b/t/pt-tcp-model/analyses.t
index b71b94f3..214128e2 100644
--- a/t/pt-tcp-model/analyses.t
+++ b/t/pt-tcp-model/analyses.t
@@ -23,6 +23,8 @@ my $in2    = "$trunk/t/pt-tcp-model/samples/in/";
 my $out    = "t/pt-tcp-model/samples/out/";
 my $output = '';
 
+$ENV{TZ}='MST7MDT';
+
 # ############################################################################
 # Basic queries that parse without problems.
 # ############################################################################
diff --git a/t/pt-trend/basics.t b/t/pt-trend/basics.t
index 4f868629..87eb4891 100644
--- a/t/pt-trend/basics.t
+++ b/t/pt-trend/basics.t
@@ -19,6 +19,8 @@ my $in   = "$trunk/t/lib/samples/slowlogs";
 my $out  = "t/pt-trend/samples/";
 my @args = ();
 
+$ENV{TZ}='MST7MDT';
+
 ok(
    no_diff(
       sub { pt_trend::main(@args, "$in/slow053.txt") },