diff --git a/lib/icinga/checkable-downtime.cpp b/lib/icinga/checkable-downtime.cpp
index d643aa163..ab35185e8 100644
--- a/lib/icinga/checkable-downtime.cpp
+++ b/lib/icinga/checkable-downtime.cpp
@@ -201,6 +201,14 @@ void Checkable::TriggerDowntime(const String& id)
 		return;
 	}
 
+	double now = Utility::GetTime();
+
+        if (now < downtime->GetStartTime() && now > downtime->GetEndTime()) {
+		Log(LogDebug, "Checkable")
+		    << "Not triggering downtime with ID '" << downtime->GetLegacyId() << "': current time is outside downtime window.";
+		return;
+	}
+
 	Log(LogNotice, "Checkable")
 		<< "Triggering downtime with ID '" << downtime->GetLegacyId() << "'.";