diff --git a/packages/class/src/config.ts b/packages/class/src/config.ts
index 5423eca..b8817a2 100644
--- a/packages/class/src/config.ts
+++ b/packages/class/src/config.ts
@@ -57,6 +57,12 @@ const untypedSchema = {
       title: "Mixed-layer switch",
       default: true,
     },
+    sw_dc: {
+      type: "boolean",
+      "ui:group": "Diurnal cycle",
+      title: "Diurnal cycle switch",
+      default: false,
+    },
     sw_wind: {
       type: "boolean",
       "ui:group": "Wind",
@@ -263,6 +269,29 @@ const untypedSchema = {
         ],
       },
     },
+    {
+      if: {
+        properties: {
+          sw_dc: {
+            const: true,
+          },
+        },
+      },
+      // biome-ignore lint/suspicious/noThenProperty: <explanation>
+      then: {
+        properties: {
+          t_dc: {
+            symbol: "T<sub>diurnal</sub>",
+            type: "number",
+            unit: "h",
+            default: 13,
+            title: "Period of diurnal cycle",
+            "ui:group": "Diurnal cycle",
+          },
+        },
+        required: ["t_dc"],
+      },
+    },
     {
       if: {
         properties: {
@@ -532,6 +561,14 @@ type NoMixedLayerConfig = {
   sw_ml?: false;
 };
 
+export type DiurnalCycleConfig = {
+  sw_dc: true;
+  t_dc: number;
+};
+export type NoDiurnalCycleConfig = {
+  sw_dc?: false;
+};
+
 export type FireConfig = {
   sw_fire: true;
   L: number;
@@ -551,7 +588,8 @@ export type NoFireConfig = {
 export type Config = GeneralConfig &
   (MixedLayerConfig | NoMixedLayerConfig) &
   (WindConfig | NoWindConfig) &
-  (FireConfig | NoFireConfig);
+  (FireConfig | NoFireConfig) &
+  (DiurnalCycleConfig | NoDiurnalCycleConfig);
 
 export type JsonSchemaOfConfig = JSONSchemaType<Config>;
 export const jsonSchemaOfConfig =
diff --git a/packages/class/src/config_utils.test.ts b/packages/class/src/config_utils.test.ts
index 4495c0a..c96e0f0 100644
--- a/packages/class/src/config_utils.test.ts
+++ b/packages/class/src/config_utils.test.ts
@@ -1,74 +1,87 @@
 import assert from "node:assert";
 import test, { describe } from "node:test";
+import type { Config } from "./config.js";
 import { pruneConfig } from "./config_utils.js";
 
 describe("pruneConfig()", () => {
   test("given 3 real configs", () => {
-    const preset = {
+    const preset: Config = {
       name: "Default",
       description: "Default configuration",
       t0: "2025-09-08T14:30:00Z",
-      theta_0: 323,
-      h_0: 200,
-      dtheta_0: 1,
-      q_0: 0.008,
-      dq_0: -0.001,
+      theta: 323,
+      h: 200,
+      dtheta: 1,
+      qt: 0.008,
+      dqt: -0.001,
       dt: 60,
       runtime: 4320,
-      wtheta: 0.1,
+      wtheta: [0.1],
       advtheta: 0,
-      gamma_theta: 0.006,
-      wq: 0.0001,
+      gamma_theta: [0.006],
+      wq: [0.0001],
       advq: 0,
-      gamma_qt: 0,
+      gamma_qt: [0],
       divU: 0,
       beta: 0.2,
+      sw_ml: true,
+      p0: 101300,
+      z_theta: [5000],
+      z_qt: [5000],
     };
-    const reference = {
+    const reference: Config = {
       name: "Higher and Hotter",
       description: "Higher h_0",
       t0: "2025-09-08T14:30:00Z",
-      h_0: 211,
-      theta_0: 323,
-      dtheta_0: 1,
-      q_0: 0.008,
-      dq_0: -0.001,
+      h: 211,
+      theta: 323,
+      dtheta: 1,
+      qt: 0.008,
+      dqt: -0.001,
       dt: 60,
       runtime: 4320,
-      wtheta: 0.1,
+      wtheta: [0.1],
       advtheta: 0,
-      gamma_theta: 0.006,
-      wq: 0.0001,
+      gamma_theta: [0.006],
+      wq: [0.0001],
       advq: 0,
-      gamma_qt: 0,
+      gamma_qt: [0],
       divU: 0,
       beta: 0.2,
+      sw_ml: true,
+      p0: 101300,
+      z_theta: [5000],
+      z_qt: [5000],
     };
-    const permutation = {
+    const permutation: Config = {
       name: "Higher",
       description: "",
       t0: "2025-09-08T14:30:00Z",
-      h_0: 222,
-      theta_0: 323,
-      dtheta_0: 1,
-      q_0: 0.008,
-      dq_0: -0.001,
+      h: 222,
+      theta: 323,
+      dtheta: 1,
+      qt: 0.008,
+      dqt: -0.001,
       dt: 60,
       runtime: 4320,
-      wtheta: 0.1,
+      wtheta: [0.1],
       advtheta: 0,
-      gamma_theta: 0.006,
-      wq: 0.0001,
+      gamma_theta: [0.006],
+      wq: [0.0001],
       advq: 0,
-      gamma_qt: 0,
+      gamma_qt: [0],
       divU: 0,
       beta: 0.212,
+      sw_ml: true,
+      p0: 101300,
+      z_theta: [5000],
+      z_qt: [5000],
     };
     const result = pruneConfig(permutation, reference, preset);
     const expected = {
       name: "Higher",
       description: "",
-      h_0: 222,
+      h: 222,
       beta: 0.212,
     };
     assert.deepEqual(result, expected);
diff --git a/packages/class/src/validate.test.ts b/packages/class/src/validate.test.ts
index f9dc391..7043dc4 100644
--- a/packages/class/src/validate.test.ts
+++ b/packages/class/src/validate.test.ts
@@ -93,6 +93,8 @@ describe("parse", () => {
       sw_ml: true,
       sw_wind: false,
       sw_fire: false,
+      sw_dc: false,
+      t_dc: 13,
     };
     assert.deepEqual(output, expected);
   });