diff --git a/just_gtfs.h b/just_gtfs.h
index a499433..4077c02 100644
--- a/just_gtfs.h
+++ b/just_gtfs.h
@@ -516,8 +516,8 @@ inline Time::Time(const std::string & raw_time_str) : raw_time(raw_time_str)
     return;
 
   const size_t len = raw_time.size();
-  if (!(len == 7 || len == 8) || (raw_time[len - 3] != ':' && raw_time[len - 6] != ':'))
-    throw InvalidFieldFormat("Time is not in [H]H:MM:SS format: " + raw_time_str);
+  if (!(len >= 7 && len <= 9) || raw_time[len - 3] != ':' || raw_time[len - 6] != ':')
+    throw InvalidFieldFormat("Time is not in [[H]H]H:MM:SS format: " + raw_time_str);
 
   hh = static_cast<uint16_t>(std::stoi(raw_time.substr(0, len - 6)));
   mm = static_cast<uint16_t>(std::stoi(raw_time.substr(len - 5, 2)));