diff --git a/core/static_src/js/timer.js b/core/static_src/js/timer.js
index e0c98449..da22211e 100644
--- a/core/static_src/js/timer.js
+++ b/core/static_src/js/timer.js
@@ -8,11 +8,14 @@
  */
 BabyBuddy.Timer = function ($) {
     var runIntervalId = null;
+    var timerId = null;
     var timerElement = null;
+    var lastUpdate = moment();
 
     var Timer = {
-        run: function(id) {
-            timerElement = $('#' + id);
+        run: function(timer_id, element_id) {
+            timerId = timer_id;
+            timerElement = $('#' + element_id);
 
             if (timerElement.length == 0) {
                 console.error('BBTimer: Timer element not found.');
@@ -27,7 +30,17 @@ BabyBuddy.Timer = function ($) {
             }
 
             runIntervalId = setInterval(this.tick, 1000);
-            return runIntervalId;
+
+            // If the page just came in to view, update the timer data with the
+            // current actual duration. This will (potentially) help mobile
+            // phones that lock with the timer page open.
+            Visibility.change(function (e, state) {
+                if (state == 'visible' && moment().diff(lastUpdate) > 2000) {
+                    clearInterval(runIntervalId);
+                    Timer.update();
+                    runIntervalId = setInterval(Timer.tick, 1000);
+                }
+            });
         },
 
         tick: function() {
@@ -54,6 +67,18 @@ BabyBuddy.Timer = function ($) {
             var h = timerElement.find('.timer-hours');
             var hours = Number(h.text());
             h.text(hours + 1);
+        },
+
+        update: function() {
+            $.get('/api/timers/' + timerId + '/', function(data) {
+                if (data && 'duration' in data) {
+                    var duration = moment.duration(data.duration);
+                    timerElement.find('.timer-hours').text(duration.hours());
+                    timerElement.find('.timer-minutes').text(duration.minutes());
+                    timerElement.find('.timer-seconds').text(duration.seconds());
+                    lastUpdate = moment();
+                }
+            });
         }
     };
 
diff --git a/gulpfile.js/config.js b/gulpfile.js/config.js
index e48e2390..ae946c7f 100644
--- a/gulpfile.js/config.js
+++ b/gulpfile.js/config.js
@@ -27,7 +27,8 @@ module.exports = {
             'node_modules/popper.js/dist/umd/popper.js',
             'node_modules/bootstrap/dist/js/bootstrap.js',
             'node_modules/moment/moment.js',
-            'node_modules/tempusdominus-bootstrap-4/build/js/tempusdominus-bootstrap-4.js'
+            'node_modules/tempusdominus-bootstrap-4/build/js/tempusdominus-bootstrap-4.js',
+            'node_modules/visibilityjs/lib/visibility.core.js'
         ],
         graph: [
             'node_modules/plotly.js/dist/plotly-cartesian.js'
diff --git a/package-lock.json b/package-lock.json
index 7ca4c74e..5c0623cd 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8048,6 +8048,11 @@
         "source-map": "0.5.6"
       }
     },
+    "visibilityjs": {
+      "version": "1.2.5",
+      "resolved": "https://registry.npmjs.org/visibilityjs/-/visibilityjs-1.2.5.tgz",
+      "integrity": "sha512-6FrRTnSvw0FrxzEOnxAJzuJ4Emy8Vw9tnwMfqxsKLmR41NFO5nJh972WeWnSh0Y434q4ThTM7l+oHast5Hqcvw=="
+    },
     "vt-pbf": {
       "version": "2.1.4",
       "resolved": "https://registry.npmjs.org/vt-pbf/-/vt-pbf-2.1.4.tgz",
diff --git a/package.json b/package.json
index d798bdd4..a14ec6b2 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,8 @@
     "pump": "^1.0.2",
     "require-dir": "^0.3.2",
     "run-sequence": "^2.2.0",
-    "tempusdominus-bootstrap-4": "^5.0.0-alpha9"
+    "tempusdominus-bootstrap-4": "^5.0.0-alpha9",
+    "visibilityjs": "^1.2.5"
   },
   "scripts": {
     "heroku-postbuild": "npm rebuild node-sass && gulp build"