diff --git a/packages/class/src/class.ts b/packages/class/src/class.ts
index 5782516..f25a172 100644
--- a/packages/class/src/class.ts
+++ b/packages/class/src/class.ts
@@ -3,6 +3,7 @@
  * @module
  */
 import type { Config, MixedLayerConfig, WindConfig } from "./config.js";
+import { qsatLiq } from "./thermodynamics.js";
 import { findInsertIndex, interpolateHourly } from "./utils.js";
 
 // Constants
@@ -209,6 +210,26 @@ export class CLASS {
     return this.wtheta + 0.61 * this.ml.theta * this.wq;
   }
 
+  /** RH at surface */
+  get RH(): number {
+    this.assertMixedLayer();
+    /** this is compatible with the inaccurate original CLASS method with rho = 1.2 */
+    const qsat_h = qsatLiq(this._cfg.p0, this.ml.theta);
+    return (100.0 * this.ml.qt) / qsat_h;
+  }
+  /** RH at h */
+  get RH_h(): number {
+    this.assertMixedLayer();
+    /** this is compatible with the inaccurate original CLASS method with rho = 1.2 */
+    const rho = 1.2;
+    const g = 9.81;
+    const cp = 1005.0;
+    const p_h = this._cfg.p0 - this.ml.h * rho * g;
+    const T_h = this.ml.theta - (g / cp) * this.ml.h;
+    const qsat_h = qsatLiq(p_h, T_h);
+    return (100.0 * this.ml.qt) / qsat_h;
+  }
+
   // Lapse rates
 
   /** Free atmosphere potential temperature lapse rate */
@@ -270,6 +291,10 @@ export class CLASS {
     return this.ml?.qt || 999;
   }
 
+  get time_hour() {
+    return this.t / 3600.0;
+  }
+
   get utcTime() {
     // export time in milliseconds since epoch so bounds calculation and
     // rendering can happen on app side
diff --git a/packages/class/src/output.ts b/packages/class/src/output.ts
index 5182789..0bfbcf7 100644
--- a/packages/class/src/output.ts
+++ b/packages/class/src/output.ts
@@ -8,12 +8,17 @@ export const outputVariables = {
   t: {
     title: "Time",
     unit: "s",
-    symbol: "t",
+    symbol: "time (s)",
+  },
+  time_hour: {
+    title: "Time",
+    unit: "h",
+    symbol: "time (h)",
   },
   utcTime: {
-    title: "Time (UTC)",
-    unit: "-",
-    symbol: "UTC",
+    title: "Time UTC",
+    unit: "h",
+    symbol: "time (h UTC)",
   },
   h: {
     title: "ABL height",
@@ -95,6 +100,16 @@ export const outputVariables = {
     unit: "m s⁻¹",
     symbol: "Δv",
   },
+  RH: {
+    title: "Relative humidity at the surface",
+    unit: "%",
+    symbol: "RH",
+  },
+  RH_h: {
+    title: "Relative humidity at h",
+    unit: "%",
+    symbol: "RH_h",
+  },
 } as const satisfies Record<string, VariableInfo>;
 
 export type OutputVariableKey = keyof typeof outputVariables;