diff --git a/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/diurnal.py b/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/diurnal.py
index 4409a3c0..fac3c48c 100644
--- a/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/diurnal.py
+++ b/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/diurnal.py
@@ -9,6 +9,7 @@ def diurnal(epw_file, return_file: str, data_type_key="Dry Bulb Temperature", co
     try:
         from ladybug.epw import EPW, AnalysisPeriod
         from ladybugtools_toolkit.ladybug_extension.datacollection import collection_to_series
+        from ladybugtools_toolkit.ladybug_extension.epw import wet_bulb_temperature
         from ladybugtools_toolkit.plot._diurnal import diurnal
         from ladybug.datacollection import HourlyContinuousCollection
         from ladybugtools_toolkit.plot.utilities import figure_to_base64
@@ -16,13 +17,15 @@ def diurnal(epw_file, return_file: str, data_type_key="Dry Bulb Temperature", co
         import matplotlib.pyplot as plt
         
         epw = EPW(epw_file)
-        data_type_key = data_type_key.replace("_"," ")
-        coll = HourlyContinuousCollection.from_dict([a for a in epw.to_dict()["data_collections"] if a["header"]["data_type"]["name"] == data_type_key][0])
-        fig = diurnal(collection_to_series(coll), title=title, period=period, color=color).get_figure()
         
+        if data_type_key == "Wet Bulb Temperature":
+            coll = wet_bulb_temperature(epw)
+        else:
+            coll = HourlyContinuousCollection.from_dict([a for a in epw.to_dict()["data_collections"] if a["header"]["data_type"]["name"] == data_type_key][0])
         
+        fig = diurnal(collection_to_series(coll),title=title, period=period, color=color).get_figure()
         return_dict = {"data": collection_metadata(coll)}
-
+        
         if save_path == None or save_path == "":
             base64 = figure_to_base64(fig, html=False)
             return_dict["figure"] = base64
diff --git a/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/heatmap.py b/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/heatmap.py
index adf74e40..cc8341fb 100644
--- a/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/heatmap.py
+++ b/LadybugTools_Engine/Python/src/ladybugtools_toolkit/bhom/wrapped/plot/heatmap.py
@@ -14,14 +14,21 @@ def heatmap(epw_file: str, data_type_key: str, colour_map: str, return_file: str
         from ladybugtools_toolkit.plot._heatmap import heatmap
         from ladybugtools_toolkit.ladybug_extension.datacollection import collection_to_series
         from ladybugtools_toolkit.bhom.wrapped.metadata.collection import collection_metadata
+        from ladybugtools_toolkit.ladybug_extension.epw import wet_bulb_temperature
         from ladybugtools_toolkit.plot.utilities import figure_to_base64
         import matplotlib.pyplot as plt
 
         if colour_map not in plt.colormaps():
             colour_map = "YlGnBu"
 
+
         epw = EPW(epw_file)
-        coll = HourlyContinuousCollection.from_dict([a for a in epw.to_dict()["data_collections"] if a["header"]["data_type"]["name"] == data_type_key][0])
+        
+        if data_type_key == "Wet Bulb Temperature":
+            coll = wet_bulb_temperature(epw)
+        else:
+            coll = HourlyContinuousCollection.from_dict([a for a in epw.to_dict()["data_collections"] if a["header"]["data_type"]["name"] == data_type_key][0])
+        
         fig = heatmap(collection_to_series(coll), cmap=colour_map).get_figure()
 
         return_dict = {}
diff --git a/LadybugTools_oM/Enum/EPWKeys.cs b/LadybugTools_oM/Enum/EPWKeys.cs
index 06a63245..0f93147b 100644
--- a/LadybugTools_oM/Enum/EPWKeys.cs
+++ b/LadybugTools_oM/Enum/EPWKeys.cs
@@ -74,6 +74,10 @@ public enum EPWKey
         [DisplayText("Total Sky Cover")]
         TotalSkyCover,
         Visibility,
+        [DisplayText("Wet Bulb Temperature")]
+        [Description("Wet bulb temperature is a calculated property of epw data.")]
+        // This was added to handle calculating wet bulb temperature with c#/python interop. If utilising this enum for other purposes, ensure that this value being selected by a user is handled correctly (either by showing an appropriate error, or calculating the wet bulb temperature)
+        WetBulbTemperature, 
         [DisplayText("Wind Direction")]
         WindDirection,
         [DisplayText("Wind Speed")]