diff --git a/CHANGELOG.md b/CHANGELOG.md
index 846a62f..4036bc4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased](https://github.com/mllam/mllam-data-prep/compare/v0.7.0...HEAD)
 
+### Changed
+- consider full time information for derived calculation of TOA radiation [\#84](https://github.com/mllam/mllam-data-prep/pull/84) @observingClouds
+
 ### Fixes
 - fix bug where coordinate selection of an unshared dimension isn't applied to subsequent ouput variables when an output variable without this dimension is processed before the others [\#90](https://github.com/mllam/mllam-data-prep/pull/90) @zweihuehner & @leifdenby
 
diff --git a/mllam_data_prep/ops/derive_variable/physical_field.py b/mllam_data_prep/ops/derive_variable/physical_field.py
index d7b9617..392b19c 100644
--- a/mllam_data_prep/ops/derive_variable/physical_field.py
+++ b/mllam_data_prep/ops/derive_variable/physical_field.py
@@ -38,10 +38,10 @@ def calculate_toa_radiation(lat, lon, time):
     # Different handling if xr.DataArray or datetime object
     if isinstance(time, xr.DataArray):
         day = time.dt.dayofyear
-        hour_utc = time.dt.hour
+        hour_utc = time.dt.hour + time.dt.minute / 60 + time.dt.second / 3600
     elif isinstance(time, datetime.datetime):
         day = time.timetuple().tm_yday
-        hour_utc = time.hour
+        hour_utc = time.hour + time.minute / 60 + time.second / 3600
     else:
         raise TypeError(
             "Expected an instance of xr.DataArray or datetime object,"