diff --git a/docs/src/leaderboard.md b/docs/src/leaderboard.md
index cb5f5f522b..b14d5a10b5 100644
--- a/docs/src/leaderboard.md
+++ b/docs/src/leaderboard.md
@@ -23,13 +23,10 @@ dictionaries must use the same short names as the keys so that the right simulat
 observational data are compared.
 
 !!! tip "Preprocessing"
-    Observational and simulational data should be preprocessed for dates and units. For
-    simulation data, monthly averages correspond to the first day following the month.
-    For instance, the monthly average corresponding to January 2010 is on the date
-    2/1/2010. Preprocessing is done to shift this date to 1/1/2010. When preprocessing
-    data, we follow the convention that the first day corresponds to the monthly average
-    for that month. For observational data, you should check the convention being followed
-    and preprocess the dates if necessary.
+    Observational and simulational data should be preprocessed for dates and units. When
+    preprocessing data, we follow the convention that the first day corresponds to the
+    monthly average for that month. For observational data, you should check the convention
+    being followed and preprocess the dates if necessary.
 
     For `obs_var_dict`, the anonymous function must take in a start date. The start date is
     used in `leaderboard.jl` to adjust the seconds in the `OutputVar` to match between start
diff --git a/experiments/ClimaEarth/Project.toml b/experiments/ClimaEarth/Project.toml
index eafdc92955..f6ddac99f9 100644
--- a/experiments/ClimaEarth/Project.toml
+++ b/experiments/ClimaEarth/Project.toml
@@ -40,7 +40,7 @@ CUDA = "5"
 ClimaAnalysis = "0.5.10"
 ClimaAtmos = "0.27, 0.28, 0.29, 0.30, 0.31"
 ClimaCalibrate = "0.1"
-ClimaDiagnostics = "0.2.6"
+ClimaDiagnostics = "0.3"
 ClimaLand = "1.1"
 ClimaOcean = "0.8.6"
 ClimaParams = "1.0"
diff --git a/experiments/ClimaEarth/leaderboard/data_sources.jl b/experiments/ClimaEarth/leaderboard/data_sources.jl
index 47167fff59..1816781613 100644
--- a/experiments/ClimaEarth/leaderboard/data_sources.jl
+++ b/experiments/ClimaEarth/leaderboard/data_sources.jl
@@ -78,7 +78,7 @@ To add a variable for the leaderboard, add a key-value pair to the dictionary
 `sim_var_dict` whose key is the short name of the variable and the value is an
 anonymous function that returns a `OutputVar`. For each variable, any
 preprocessing should be done in the corresponding anonymous function which
-includes unit conversion and shifting the dates.
+includes unit conversion.
 
 The variable should have only three dimensions: latitude, longitude, and time.
 """
@@ -101,7 +101,6 @@ function get_sim_var_dict(diagnostics_folder_path)
                     "mm/day",
                     conversion_function = x -> x .* Float32(-86400),
                 )
-                sim_var = ClimaAnalysis.shift_to_start_of_previous_month(sim_var)
                 return sim_var
             end
     )
@@ -116,7 +115,6 @@ function get_sim_var_dict(diagnostics_folder_path)
                         reduction = "average",
                         period = "1M",
                     )
-                    sim_var = ClimaAnalysis.shift_to_start_of_previous_month(sim_var)
                     return sim_var
                 end
         )
@@ -255,7 +253,7 @@ To add a variable for the leaderboard, add a key-value pair to the dictionary
 `sim_var_dict` whose key is the short name of the variable and the value is an
 anonymous function that returns a `OutputVar`. For each variable, any
 preprocessing should be done in the corresponding anonymous function which
-includes unit conversion and shifting the dates.
+includes unit conversion.
 
 The variable should have only four dimensions: latitude, longitude, time, and
 pressure. The units of pressure should be in hPa.
@@ -305,8 +303,6 @@ function get_sim_var_in_pfull_dict(diagnostics_folder_path)
                         sim_var_windowed,
                         pfull_var_windowed,
                     )
-                    sim_in_pfull_var =
-                        ClimaAnalysis.shift_to_start_of_previous_month(sim_in_pfull_var)
                     sim_in_pfull_var = ClimaAnalysis.convert_dim_units(
                         sim_in_pfull_var,
                         "pfull",