diff --git a/esphome/energymonitor.yaml b/esphome/energymonitor.yaml
index 6a3a676..22a1197 100644
--- a/esphome/energymonitor.yaml
+++ b/esphome/energymonitor.yaml
@@ -1,5 +1,5 @@
 substitutions:
-  device_description: "M5Stack Core dashboard for Home Assistant energy and internet usage, with analog/digital clock and WireGuard"
+  device_description: "M5Stack Core dashboard for Home Assistant energy and internet usage, SCD30 room climate, analog/digital clock and WireGuard"
   name: "energymonitor"
   friendly_name: "Energy Monitor"
 
@@ -87,6 +87,16 @@ spi:
   clk_pin: GPIO18
   mosi_pin: GPIO23
 
+# Grove Port A: white = SDA, yellow = SCL, red = 5 V, black = GND.
+i2c:
+  id: grove_i2c
+  sda: GPIO21
+  scl: GPIO22
+  frequency: 50kHz
+  # Allow clock stretching by the SCD30 (ESP32 hardware limit).
+  timeout: 13ms
+  scan: true
+
 output:
   - platform: gpio
     pin: GPIO32
@@ -170,6 +180,30 @@ globals:
     type: int
     restore_value: true
     initial_value: '0'
+  - id: climate_graph_view
+    type: bool
+    restore_value: true
+    initial_value: 'false'
+  - id: climate_co2_history
+    type: std::array<float, 361>
+    restore_value: false
+    initial_value: 'std::array<float, 361>{}'
+  - id: climate_temperature_history
+    type: std::array<float, 361>
+    restore_value: false
+    initial_value: 'std::array<float, 361>{}'
+  - id: climate_humidity_history
+    type: std::array<float, 361>
+    restore_value: false
+    initial_value: 'std::array<float, 361>{}'
+  - id: climate_history_next
+    type: int
+    restore_value: false
+    initial_value: '0'
+  - id: climate_history_count
+    type: int
+    restore_value: false
+    initial_value: '0'
   # 361 ten-second samples span one hour; unfilled slots are never drawn.
   - id: internet_download_history
     type: std::array<float, 361>
@@ -189,6 +223,26 @@ globals:
     initial_value: '0'
 
 sensor:
+  - platform: scd30
+    id: room_climate
+    i2c_id: grove_i2c
+    address: 0x61
+    update_interval: 5s
+    co2:
+      id: scd30_co2
+      name: "CO2"
+      filters:
+        - timeout: 30s
+    temperature:
+      id: scd30_temperature
+      name: "Temperature"
+      filters:
+        - timeout: 30s
+    humidity:
+      id: scd30_humidity
+      name: "Humidity"
+      filters:
+        - timeout: 30s
   # WiFi signal strength
   - platform: wifi_signal
     name: "WiFi Signalstärke"
@@ -336,6 +390,17 @@ interval:
           id(internet_history_next) = (slot + 1) % 361;
           if (id(internet_history_count) < 361) id(internet_history_count)++;
 
+          // Local measurements keep recording even without Home Assistant or Wi-Fi.
+          const int climate_slot = id(climate_history_next);
+          auto sample_climate = [](sensor::Sensor *source) -> float {
+            return source->has_state() && std::isfinite(source->state) ? source->state : NAN;
+          };
+          id(climate_co2_history)[climate_slot] = sample_climate(id(scd30_co2));
+          id(climate_temperature_history)[climate_slot] = sample_climate(id(scd30_temperature));
+          id(climate_humidity_history)[climate_slot] = sample_climate(id(scd30_humidity));
+          id(climate_history_next) = (climate_slot + 1) % 361;
+          if (id(climate_history_count) < 361) id(climate_history_count)++;
+
 script:
   - id: refresh_display
     then:
@@ -344,7 +409,7 @@ script:
       - component.update: tft
   - id: show_previous_page
     then:
-      - lambda: id(page_index) = (id(page_index) + 4 - 1) % 4;
+      - lambda: id(page_index) = (id(page_index) + 5 - 1) % 5;
       - script.execute: refresh_display
   - id: toggle_page_mode
     then:
@@ -357,11 +422,13 @@ script:
             id(clock_digital_view) = !id(clock_digital_view);
           } else if (id(page_index) == 3) {
             id(internet_view) = (id(internet_view) + 1) % 3;
+          } else if (id(page_index) == 4) {
+            id(climate_graph_view) = !id(climate_graph_view);
           }
       - script.execute: refresh_display
   - id: show_next_page
     then:
-      - lambda: id(page_index) = (id(page_index) + 1) % 4;
+      - lambda: id(page_index) = (id(page_index) + 1) % 5;
       - script.execute: refresh_display
 
 button:
@@ -885,6 +952,98 @@ display:
         }
       }
 
+      if (id(page_index) == 4) {
+        const Color co2_color(143, 190, 223);
+        const Color temperature_color(255, 170, 40);
+        const Color humidity_color(93, 207, 140);
+        const bool co2_valid = id(scd30_co2).has_state() && std::isfinite(id(scd30_co2).state);
+        const bool temperature_valid = id(scd30_temperature).has_state()
+            && std::isfinite(id(scd30_temperature).state);
+        const bool humidity_valid = id(scd30_humidity).has_state()
+            && std::isfinite(id(scd30_humidity).state);
+        if (!id(climate_graph_view)) {
+          draw_page_title("Raumklima");
+          it.print(160, 38, id(font_small), co2_color, TextAlign::TOP_CENTER, "CO2");
+          it.printf(160, 58, id(font_value), co2_color, TextAlign::TOP_CENTER,
+                    co2_valid ? "%.0f ppm" : "-- ppm", id(scd30_co2).state);
+          it.print(80, 140, id(font_small), temperature_color, TextAlign::TOP_CENTER, "Temperatur");
+          it.printf(80, 164, id(font_title), temperature_color, TextAlign::TOP_CENTER,
+                    temperature_valid ? "%.1f °C" : "-- °C", id(scd30_temperature).state);
+          it.print(240, 140, id(font_small), humidity_color, TextAlign::TOP_CENTER, "Feuchte");
+          it.printf(240, 164, id(font_title), humidity_color, TextAlign::TOP_CENTER,
+                    humidity_valid ? "%.1f %%" : "-- %%", id(scd30_humidity).state);
+          if (!co2_valid && !temperature_valid && !humidity_valid) {
+            it.print(160, 204, id(font_device), Color::WHITE, TextAlign::TOP_CENTER,
+                     "Warte auf SCD30-Messwerte");
+          }
+        } else {
+          draw_page_title("Raumklima · 1 h");
+          const int left = 28, right = 308;
+          const int count = id(climate_history_count);
+          const char *labels[] = {"CO2", "Temperatur", "Feuchte"};
+          const char *units[] = {"ppm", "°C", "%"};
+          const Color colors[] = {co2_color, temperature_color, humidity_color};
+          const std::array<float, 361> *histories[] = {
+              &id(climate_co2_history), &id(climate_temperature_history), &id(climate_humidity_history)};
+          const float scale_steps[] = {100.0f, 1.0f, 5.0f};
+          const float minimum_ranges[] = {200.0f, 2.0f, 10.0f};
+          for (int graph = 0; graph < 3; graph++) {
+            const int top = 52 + graph * 54;
+            const int bottom = top + 31;
+            float minimum = INFINITY, maximum = -INFINITY;
+            for (int sample = 0; sample < count; sample++) {
+              const int slot = (id(climate_history_next) - count + sample + 361) % 361;
+              const float value = (*histories[graph])[slot];
+              if (std::isfinite(value)) {
+                minimum = fminf(minimum, value);
+                maximum = fmaxf(maximum, value);
+              }
+            }
+            const bool has_samples = std::isfinite(minimum);
+            if (has_samples) {
+              const float middle = (minimum + maximum) / 2.0f;
+              const float range = fmaxf(maximum - minimum, minimum_ranges[graph]);
+              minimum = floorf((middle - range / 2.0f) / scale_steps[graph]) * scale_steps[graph];
+              maximum = ceilf((middle + range / 2.0f) / scale_steps[graph]) * scale_steps[graph];
+            }
+            it.print(12, top - 16, id(font_device), colors[graph], labels[graph]);
+            if (has_samples) {
+              it.printf(right, top - 16, id(font_device), colors[graph], TextAlign::TOP_RIGHT,
+                        "%.0f - %.0f %s", minimum, maximum, units[graph]);
+            } else {
+              it.print(right, top - 16, id(font_device), colors[graph], TextAlign::TOP_RIGHT,
+                       "Warte auf Messwerte");
+            }
+            for (int minute = 0; minute <= 60; minute += 15) {
+              const int x = left + minute * (right - left) / 60;
+              it.line(x, top, x, bottom, Color(42, 42, 42));
+            }
+            it.line(left, top, right, top, Color(42, 42, 42));
+            it.line(left, bottom, right, bottom, Color(42, 42, 42));
+            int previous_x = 0, previous_y = 0;
+            bool previous_valid = false;
+            for (int sample = 0; sample < count; sample++) {
+              const int slot = (id(climate_history_next) - count + sample + 361) % 361;
+              const float value = (*histories[graph])[slot];
+              const bool valid = std::isfinite(value);
+              const int x = right - (count - 1 - sample) * (right - left) / 360;
+              if (valid) {
+                const int y = bottom - lroundf((value - minimum) / (maximum - minimum) * (bottom - top));
+                it.line(previous_valid ? previous_x : x, previous_valid ? previous_y : y,
+                        x, y, colors[graph]);
+                previous_x = x;
+                previous_y = y;
+              }
+              previous_valid = valid;
+            }
+          }
+          it.print(left, 202, id(font_device), Color::WHITE, "-60 min");
+          it.print((left + right) / 2, 202, id(font_device), Color::WHITE,
+                   TextAlign::TOP_CENTER, "-30 min");
+          it.print(right, 202, id(font_device), Color::WHITE, TextAlign::TOP_RIGHT, "Jetzt");
+        }
+      }
+
       // Labels correspond to the left (A) and right (C) hardware buttons.
       it.printf(8, 239, id(font_small), Color::WHITE, TextAlign::BOTTOM_LEFT,
                 "< Zurück");
@@ -906,4 +1065,16 @@ display:
                   "%s · %d / 3", id(internet_view) == 0 ? "Live"
                       : id(internet_view) == 1 ? "Verlauf" : "Volumen",
                   id(internet_view) + 1);
+      } else if (id(page_index) == 4) {
+        it.printf(160, 239, id(font_small), Color::WHITE, TextAlign::BOTTOM_CENTER,
+                  "%s · %d / 2", id(climate_graph_view) ? "Verlauf" : "Live",
+                  id(climate_graph_view) ? 2 : 1);
+      }
+
+      // Draw last so high CO2 remains visible on every page and subpage.
+      if (id(scd30_co2).has_state() && std::isfinite(id(scd30_co2).state)
+          && id(scd30_co2).state > 1200.0f) {
+        const Color warning_color = id(scd30_co2).state > 1600.0f
+            ? Color(255, 0, 0) : Color(255, 170, 40);
+        it.filled_circle(160, 120, 5, warning_color);
       }