diff --git a/docs/API.md b/docs/API.md
index 6b57311..e886b84 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -963,3 +963,13 @@ The Cargo ESP currently supports 4 temperature sensor slots.
 Temperature sensor `group` values are free-form text in the WebUI. Entering a new group name effectively creates that group. The dashboard overview shows the first two available non-weather groups by priority. Multiple sensors in the same group are combined into one tile, such as `34°/45°`.
 
 Sensors marked `weather: true` are excluded from the temperature card and shown in the top status strip as `OUT ##°`.
+
+### Temperature High Alerts
+
+Each temperature sensor supports optional high-temperature alerting:
+
+- `high_alert_enabled`
+- `high_alert_f`
+- `high_alert`
+
+When enabled and the live sensor temperature exceeds the configured threshold, the Cargo ESP includes `high_alert: true` for that sensor in `/api/v1/status`. The ESP32-S3 dashboard colors the affected grouped temperature tile red if any sensor in that displayed group is in alert.
diff --git a/docs/dashboard-esp32s3.md b/docs/dashboard-esp32s3.md
index de78b1a..b4a7cd3 100644
--- a/docs/dashboard-esp32s3.md
+++ b/docs/dashboard-esp32s3.md
@@ -281,3 +281,13 @@ The Cargo ESP currently supports 4 temperature sensor slots.
 Temperature sensor `group` values are free-form text in the WebUI. Entering a new group name effectively creates that group. The dashboard overview shows the first two available non-weather groups by priority. Multiple sensors in the same group are combined into one tile, such as `34°/45°`.
 
 Sensors marked `weather: true` are excluded from the temperature card and shown in the top status strip as `OUT ##°`.
+
+### Temperature High Alerts
+
+Each temperature sensor supports optional high-temperature alerting:
+
+- `high_alert_enabled`
+- `high_alert_f`
+- `high_alert`
+
+When enabled and the live sensor temperature exceeds the configured threshold, the Cargo ESP includes `high_alert: true` for that sensor in `/api/v1/status`. The ESP32-S3 dashboard colors the affected grouped temperature tile red if any sensor in that displayed group is in alert.
diff --git a/docs/project-state.md b/docs/project-state.md
index 6aacfb8..78781e7 100644
--- a/docs/project-state.md
+++ b/docs/project-state.md
@@ -348,3 +348,13 @@ The Cargo ESP currently supports 4 temperature sensor slots.
 Temperature sensor `group` values are free-form text in the WebUI. Entering a new group name effectively creates that group. The dashboard overview shows the first two available non-weather groups by priority. Multiple sensors in the same group are combined into one tile, such as `34°/45°`.
 
 Sensors marked `weather: true` are excluded from the temperature card and shown in the top status strip as `OUT ##°`.
+
+### Temperature High Alerts
+
+Each temperature sensor supports optional high-temperature alerting:
+
+- `high_alert_enabled`
+- `high_alert_f`
+- `high_alert`
+
+When enabled and the live sensor temperature exceeds the configured threshold, the Cargo ESP includes `high_alert: true` for that sensor in `/api/v1/status`. The ESP32-S3 dashboard colors the affected grouped temperature tile red if any sensor in that displayed group is in alert.
diff --git a/firmware/esp32-s3-dashboard/dashboard_config.h b/firmware/esp32-s3-dashboard/dashboard_config.h
index fed8af1..f84270e 100644
--- a/firmware/esp32-s3-dashboard/dashboard_config.h
+++ b/firmware/esp32-s3-dashboard/dashboard_config.h
@@ -1,6 +1,6 @@
 #pragma once
 
-static const char *DASHBOARD_VERSION = "0.1.40-temp-two-groups";
+static const char *DASHBOARD_VERSION = "0.1.41-temp-alerts";
 
 // Update these if your Cargo ESP AP credentials are different.
 static const char *CARGO_WIFI_SSID = "OverlandController";
diff --git a/firmware/esp32-s3-dashboard/esp32-s3-dashboard.ino b/firmware/esp32-s3-dashboard/esp32-s3-dashboard.ino
index 36a3c5a..f5ea4ab 100644
--- a/firmware/esp32-s3-dashboard/esp32-s3-dashboard.ino
+++ b/firmware/esp32-s3-dashboard/esp32-s3-dashboard.ino
@@ -19,8 +19,10 @@ static lv_obj_t *battery_charge_pulse_arc = nullptr;
 static lv_obj_t *battery_current_label = nullptr;
 static lv_obj_t *battery_estimate_label = nullptr;
 static lv_obj_t *battery_soc_label = nullptr;
+static lv_obj_t *temp_tile_objs[2] = {nullptr};
 static lv_obj_t *temp_tile_value_labels[2] = {nullptr};
 static lv_obj_t *temp_tile_name_labels[2] = {nullptr};
+static bool last_temp_tile_alert[2] = {false, false};
 static lv_obj_t *system_status_label = nullptr;
 static lv_obj_t *wifi_icon_label = nullptr;
 static lv_obj_t *wifi_bars_obj[4] = {nullptr};
@@ -597,6 +599,34 @@ static void update_system_status_label()
 
 
 
+
+static void update_temp_tile_alert_style(int index, bool alert)
+{
+    if (index < 0 || index >= 2 || temp_tile_objs[index] == nullptr) {
+        return;
+    }
+
+    if (last_temp_tile_alert[index] == alert) {
+        return;
+    }
+
+    last_temp_tile_alert[index] = alert;
+
+    lvgl_port_lock(-1);
+
+    if (alert) {
+        lv_obj_set_style_bg_color(temp_tile_objs[index], lv_color_hex(0x7A271A), 0);
+        lv_obj_set_style_border_color(temp_tile_objs[index], lv_color_hex(0xF97066), 0);
+        lv_obj_set_style_border_width(temp_tile_objs[index], 3, 0);
+    } else {
+        lv_obj_set_style_bg_color(temp_tile_objs[index], lv_color_hex(0x17202A), 0);
+        lv_obj_set_style_border_color(temp_tile_objs[index], lv_color_hex(0x2F3A46), 0);
+        lv_obj_set_style_border_width(temp_tile_objs[index], 2, 0);
+    }
+
+    lvgl_port_unlock();
+}
+
 static void update_overview_widgets()
 {
     String current_text = "Idle";
@@ -687,6 +717,7 @@ static void parse_status_json(const String &body)
             String group;
             int priority;
             int rounded_f;
+            bool high_alert;
         };
 
         TempDisplayItem items[4];
@@ -702,6 +733,7 @@ static void parse_status_json(const String &body)
             }
 
             float temp_f = (float)(temp["temperature_f"] | 0.0);
+            bool high_alert = temp["high_alert"] | false;
 
             if (weather) {
                 outside_status = "OUT ";
@@ -716,7 +748,6 @@ static void parse_status_json(const String &body)
             String name = raw_name && raw_name[0] ? String(raw_name) : String("cabin");
             String group = normalize_temp_group(String(raw_group), name, false);
 
-            // Outside/weather is shown in the status strip, not the main temp card.
             if (group == "outside") {
                 outside_status = "OUT ";
                 outside_status += String((int)round(temp_f));
@@ -728,7 +759,8 @@ static void parse_status_json(const String &body)
                 items[item_count] = {
                     group,
                     temp["priority"] | 99,
-                    (int)round(temp_f)
+                    (int)round(temp_f),
+                    high_alert
                 };
                 item_count++;
             }
@@ -749,13 +781,15 @@ static void parse_status_json(const String &body)
 
         String group_names[2] = {"--", "--"};
         String group_values[2] = {"--", "--"};
+        bool group_alerts[2] = {false, false};
         int group_count = 0;
 
         for (int i = 0; i < item_count; i++) {
             int slot = -1;
+            String display_group = display_temp_group_name(items[i].group);
 
             for (int g = 0; g < group_count; g++) {
-                if (group_names[g] == display_temp_group_name(items[i].group)) {
+                if (group_names[g] == display_group) {
                     slot = g;
                     break;
                 }
@@ -767,7 +801,7 @@ static void parse_status_json(const String &body)
                 }
 
                 slot = group_count;
-                group_names[slot] = display_temp_group_name(items[i].group);
+                group_names[slot] = display_group;
                 group_values[slot] = "";
                 group_count++;
             }
@@ -780,6 +814,10 @@ static void parse_status_json(const String &body)
             }
 
             group_values[slot] += value;
+
+            if (items[i].high_alert) {
+                group_alerts[slot] = true;
+            }
         }
 
         update_outside_status_temp(outside_status);
@@ -787,6 +825,7 @@ static void parse_status_json(const String &body)
         for (int i = 0; i < 2; i++) {
             set_label_text_if_changed(temp_tile_value_labels[i], last_temp_tile_value_text[i], group_values[i]);
             set_label_text_if_changed(temp_tile_name_labels[i], last_temp_tile_name_text[i], group_names[i]);
+            update_temp_tile_alert_style(i, group_alerts[i]);
         }
     }
 
@@ -1016,6 +1055,7 @@ static void create_overland_overview_screen()
 
     for (int i = 0; i < 2; i++) {
         lv_obj_t *tile = lv_obj_create(temp_card);
+        temp_tile_objs[i] = tile;
         lv_obj_set_size(tile, temp_tile_w, temp_tile_h);
         lv_obj_align(tile, LV_ALIGN_TOP_MID, 0, temp_tile_y[i]);
         lv_obj_set_style_radius(tile, 18, 0);
diff --git a/firmware/esp32/overland-controller/app_config.cpp b/firmware/esp32/overland-controller/app_config.cpp
index 39431ed..4f36755 100644
--- a/firmware/esp32/overland-controller/app_config.cpp
+++ b/firmware/esp32/overland-controller/app_config.cpp
@@ -40,7 +40,9 @@ void loadDefaultConfig() {
             i < appConfig.tempSensorCount,
             false,
             "cabin",
-            i + 1
+            i + 1,
+            false,
+            90.0
         };
     }
 
@@ -111,6 +113,14 @@ void loadConfig() {
                 (prefix + "priority").c_str(),
                 appConfig.tempSensors[i].priority
             );
+            appConfig.tempSensors[i].highAlertEnabled = preferences.getBool(
+                (prefix + "high_alert_enabled").c_str(),
+                appConfig.tempSensors[i].highAlertEnabled
+            );
+            appConfig.tempSensors[i].highAlertF = preferences.getFloat(
+                (prefix + "high_alert_f").c_str(),
+                appConfig.tempSensors[i].highAlertF
+            );
         }
 
         appConfig.bms.enabled = preferences.getBool("bms_enabled", appConfig.bms.enabled);
@@ -203,7 +213,11 @@ void printConfig() {
         Serial.print(" / group ");
         Serial.print(appConfig.tempSensors[i].group);
         Serial.print(" / priority ");
-        Serial.println(appConfig.tempSensors[i].priority);
+        Serial.print(appConfig.tempSensors[i].priority);
+        Serial.print(" / high alert ");
+        Serial.print(appConfig.tempSensors[i].highAlertEnabled ? "on" : "off");
+        Serial.print(" @ ");
+        Serial.println(appConfig.tempSensors[i].highAlertF);
     }
 
     Serial.println("  BMS:");
diff --git a/firmware/esp32/overland-controller/app_config.h b/firmware/esp32/overland-controller/app_config.h
index 556fe41..a3bf5ca 100644
--- a/firmware/esp32/overland-controller/app_config.h
+++ b/firmware/esp32/overland-controller/app_config.h
@@ -24,6 +24,8 @@ struct TempSensorConfig {
     bool weather;
     String group;
     int priority;
+    bool highAlertEnabled;
+    float highAlertF;
 };
 
 struct BmsConfig {
diff --git a/firmware/esp32/overland-controller/overland-controller.ino b/firmware/esp32/overland-controller/overland-controller.ino
index 45c23c9..11415b4 100644
--- a/firmware/esp32/overland-controller/overland-controller.ino
+++ b/firmware/esp32/overland-controller/overland-controller.ino
@@ -1196,6 +1196,14 @@ function renderConfigControls(data){
         <label class="inputHelp" for="tempPriority${i}">Priority</label>
         <input id="tempPriority${i}" type="number" min="1" max="99" step="1" placeholder="1" oninput="markConfigFieldTouched('tempPriority${i}')">
 
+        <div class="tempAlertConfig">
+          <label class="tempCheck">
+            <input id="tempHighAlertEnabled${i}" type="checkbox" onchange="markConfigFieldTouched('tempHighAlertEnabled${i}')">
+            High Alert
+          </label>
+          <input id="tempHighAlertF${i}" type="number" min="-40" max="200" step="1" placeholder="90" oninput="markConfigFieldTouched('tempHighAlertF${i}')">
+        </div>
+
         <div class="tempConfigControls">
           <label class="tempCheck">
             <input id="tempEnabled${i}" type="checkbox" onchange="markConfigFieldTouched('tempEnabled${i}'); saveTempConfig()">
@@ -1234,6 +1242,16 @@ function renderConfigControls(data){
     if(priority && !configTouched["tempPriority"+i] && document.activeElement!==priority){
       priority.value=t.priority||i+1;
     }
+
+    const highAlertEnabled=$("tempHighAlertEnabled"+i);
+    if(highAlertEnabled && !configTouched["tempHighAlertEnabled"+i] && document.activeElement!==highAlertEnabled){
+      highAlertEnabled.checked=!!t.high_alert_enabled;
+    }
+
+    const highAlertF=$("tempHighAlertF"+i);
+    if(highAlertF && !configTouched["tempHighAlertF"+i] && document.activeElement!==highAlertF){
+      highAlertF.value=t.high_alert_f ?? 90;
+    }
   });
 }
 
@@ -1278,6 +1296,8 @@ async function saveTempConfig(){
     const weather=$("tempWeather"+i)?.checked || false;
     const group=$("tempGroup"+i)?.value || temps[i].group || "cabin";
     const priority=parseInt($("tempPriority"+i)?.value || temps[i].priority || (i+1),10);
+    const highAlertEnabled=$("tempHighAlertEnabled"+i)?.checked || false;
+    const highAlertF=parseFloat($("tempHighAlertF"+i)?.value || temps[i].high_alert_f || 90);
 
     await fetch(api("/config/temp"),{
       method:"POST",
@@ -1289,7 +1309,9 @@ async function saveTempConfig(){
         enabled:enabled,
         weather:weather,
         group:group,
-        priority:priority
+        priority:priority,
+        high_alert_enabled:highAlertEnabled,
+        high_alert_f:highAlertF
       })
     });
   }
@@ -1299,7 +1321,7 @@ async function saveTempConfig(){
   alert("Temperature config saved");
   clearConfigTouched([
     "tempEnabledCount",
-    ...temps.flatMap((_,i)=>["tempName"+i,"tempEnabled"+i,"tempWeather"+i,"tempGroup"+i,"tempPriority"+i])
+    ...temps.flatMap((_,i)=>["tempName"+i,"tempEnabled"+i,"tempWeather"+i,"tempGroup"+i,"tempPriority"+i,"tempHighAlertEnabled"+i,"tempHighAlertF"+i])
   ]);
 }
 
@@ -2029,6 +2051,8 @@ void buildConfigDocument(JsonObject doc) {
         temp["weather"] = appConfig.tempSensors[i].weather;
         temp["group"] = appConfig.tempSensors[i].group;
         temp["priority"] = appConfig.tempSensors[i].priority;
+        temp["high_alert_enabled"] = appConfig.tempSensors[i].highAlertEnabled;
+        temp["high_alert_f"] = appConfig.tempSensors[i].highAlertF;
     }
 }
 
@@ -2224,6 +2248,8 @@ void applyImportedConfig(JsonObject doc) {
             if (temp["weather"].is<bool>()) appConfig.tempSensors[index].weather = temp["weather"].as<bool>();
             if (temp["group"].is<String>()) appConfig.tempSensors[index].group = temp["group"].as<String>();
             if (temp["priority"].is<int>()) appConfig.tempSensors[index].priority = temp["priority"].as<int>();
+            if (temp["high_alert_enabled"].is<bool>()) appConfig.tempSensors[index].highAlertEnabled = temp["high_alert_enabled"].as<bool>();
+            if (temp["high_alert_f"].is<float>()) appConfig.tempSensors[index].highAlertF = temp["high_alert_f"].as<float>();
         }
     }
 
@@ -2331,9 +2357,15 @@ void buildStatusDocument(JsonDocument& doc) {
         temp["weather"] = appConfig.tempSensors[i].weather;
         temp["group"] = appConfig.tempSensors[i].group;
         temp["priority"] = appConfig.tempSensors[i].priority;
+        temp["high_alert_enabled"] = appConfig.tempSensors[i].highAlertEnabled;
+        temp["high_alert_f"] = appConfig.tempSensors[i].highAlertF;
         temp["online"] = sensors.online[i];
         if (sensors.online[i]) {
             temp["temperature_f"] = sensors.tempsF[i];
+        temp["high_alert"] =
+            appConfig.tempSensors[i].highAlertEnabled &&
+            sensors.tempOnline[i] &&
+            sensors.tempsF[i] > appConfig.tempSensors[i].highAlertF;
         } else {
             temp["temperature_f"] = nullptr;
         }
@@ -2477,6 +2509,8 @@ void sendConfigResponse(Stream& output, bool ok = true) {
         temp["weather"] = appConfig.tempSensors[i].weather;
         temp["group"] = appConfig.tempSensors[i].group;
         temp["priority"] = appConfig.tempSensors[i].priority;
+        temp["high_alert_enabled"] = appConfig.tempSensors[i].highAlertEnabled;
+        temp["high_alert_f"] = appConfig.tempSensors[i].highAlertF;
     }
 
     serializeJson(doc, output);
@@ -3460,6 +3494,8 @@ void handleUpdateTempSensorConfig() {
     if (doc["weather"].is<bool>()) appConfig.tempSensors[index].weather = doc["weather"].as<bool>();
     if (doc["group"].is<String>()) appConfig.tempSensors[index].group = doc["group"].as<String>();
     if (doc["priority"].is<int>()) appConfig.tempSensors[index].priority = doc["priority"].as<int>();
+    if (doc["high_alert_enabled"].is<bool>()) appConfig.tempSensors[index].highAlertEnabled = doc["high_alert_enabled"].as<bool>();
+    if (doc["high_alert_f"].is<float>()) appConfig.tempSensors[index].highAlertF = doc["high_alert_f"].as<float>();
 
     sendOkConfig();
 }
@@ -3602,6 +3638,8 @@ void handleTempClear() {
             appConfig.tempSensors[i].weather = false;
             appConfig.tempSensors[i].group = "cabin";
             appConfig.tempSensors[i].priority = i + 1;
+            appConfig.tempSensors[i].highAlertEnabled = false;
+            appConfig.tempSensors[i].highAlertF = 90.0;
             sensors.tempsF[i] = -127.0;
             sensors.online[i] = false;
         }
@@ -3640,6 +3678,8 @@ void handleTempClear() {
     appConfig.tempSensors[configIndex].weather = false;
     appConfig.tempSensors[configIndex].group = "cabin";
     appConfig.tempSensors[configIndex].priority = configIndex + 1;
+    appConfig.tempSensors[configIndex].highAlertEnabled = false;
+    appConfig.tempSensors[configIndex].highAlertF = 90.0;
     sensors.tempsF[configIndex] = -127.0;
     sensors.online[configIndex] = false;