diff --git a/CHANGELOG b/CHANGELOG
index 76a6041e6..54ad37d4f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,10 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o Avoid an unnecessary assert failure in timing.cc when printing estimated
+  completion time. Instead, we'll output a diagnostic error message:
+    Timing error: localtime(n) is NULL
+  where "n" is some number that is causing problems. [Jean-Guilhem Nousse]
+
 o [NSE] Removed the obsolete script ip-geolocation-geobytes. [Paulino Calderon]
 
 o Added --script-timeout option for limiting run time for every
diff --git a/timing.cc b/timing.cc
index abdda0dad..1c1be23ed 100644
--- a/timing.cc
+++ b/timing.cc
@@ -707,13 +707,22 @@ bool ScanProgressMeter::printStats(double perc_done,
   /* Get the estimated time of day at completion */
   timet = last_est.tv_sec;
   ltime = localtime(&timet);
-  assert(ltime);
 
-  log_write(LOG_STDOUT, "%s Timing: About %.2f%% done; ETC: %02d:%02d (%.f:%02.f:%02.f remaining)\n",
-      scantypestr, perc_done * 100, ltime->tm_hour, ltime->tm_min,
-      floor(time_left_s / 60.0 / 60.0),
-      floor(fmod(time_left_s / 60.0, 60.0)),
-      floor(fmod(time_left_s, 60.0)));
+  if (ltime) {
+    log_write(LOG_STDOUT, "%s Timing: About %.2f%% done; ETC: %02d:%02d (%.f:%02.f:%02.f remaining)\n",
+        scantypestr, perc_done * 100, ltime->tm_hour, ltime->tm_min,
+        floor(time_left_s / 60.0 / 60.0),
+        floor(fmod(time_left_s / 60.0, 60.0)),
+        floor(fmod(time_left_s, 60.0)));
+  }
+  else {
+    log_write(LOG_STDERR, "Timing error: localtime(%f) is NULL\n", (double) timet);
+    log_write(LOG_STDOUT, "%s Timing: About %.2f%% done; ETC: Unknown (%.f:%02.f:%02.f remaining)\n",
+        scantypestr, perc_done * 100,
+        floor(time_left_s / 60.0 / 60.0),
+        floor(fmod(time_left_s / 60.0, 60.0)),
+        floor(fmod(time_left_s, 60.0)));
+  }
   xml_open_start_tag("taskprogress");
   xml_attribute("task", "%s", scantypestr);
   xml_attribute("time", "%lu", (unsigned long) now->tv_sec);