--- a/toolkit/content/aboutTelemetry.js
+++ b/toolkit/content/aboutTelemetry.js
@@ -415,20 +415,28 @@ var PingPicker = {
     const today = new Date();
     today.setHours(0, 0, 0, 0);
     const yesterday = new Date(today);
     yesterday.setDate(today.getDate() - 1);
 
     for (let p of this._archivedPings) {
       pingTypes.add(p.type);
       const pingDate = new Date(p.timestampCreated);
-      const datetimeText = new Services.intl.DateTimeFormat(undefined, {
-          dateStyle: "short",
-          timeStyle: "medium"
-        }).format(pingDate);
+      const isoDate = pingDate.toISOString().substring(0, 10);
+      const minutes = pingDate.getMinutes();
+      const seconds = pingDate.getSeconds();
+      let hours = pingDate.getHours();
+      let period = "AM";
+      if (hours >= 12) {
+        period = "PM";
+        hours = hours % 12;
+      }
+      const isoTime = hours + ":" + minutes + ":" + seconds + " " + period;
+      const datetimeText = isoDate + ", " + isoTime;
+
       const pingName = `${datetimeText}, ${p.type}`;
 
       let option = document.createElement("option");
       let content = document.createTextNode(pingName);
       option.appendChild(content);
       option.setAttribute("value", p.id);
       option.dataset.type = p.type;
       option.dataset.date = datetimeText;