diff --git a/modules/util/util.py b/modules/util/util.py
index e86cd3779135f14e4b8d99515a29b92695ddb7c4..7cbed72c11dfb8532390cbab95d7618ba31aa467 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -185,21 +185,21 @@ def value_to_index(nda, value):
     return idx
 
 
-# array solzen must be degrees, missing values must NaN. For small 50x50km regions only
-def is_night(solzen, test_angle=80.0, threshold=0.10):
+# array solzen must be degrees, missing values must NaN. For small roughly 50x50km regions only
+def is_day(solzen, test_angle=80.0):
     solzen = solzen.flatten()
     solzen = solzen[np.invert(np.isnan(solzen))]
-    if len(solzen) == 0 or (np.sum(solzen > test_angle) / len(solzen)) > threshold:
-        return True
-    else:
+    if len(solzen) == 0 or np.sum(solzen <= test_angle) < len(solzen):
         return False
+    else:
+        return True
 
 
 # array solzen must be degrees, missing values must NaN. For small roughly 50x50km regions only
-def is_day(solzen, test_angle=75.0):
+def is_night(solzen, test_angle=100.0):
     solzen = solzen.flatten()
     solzen = solzen[np.invert(np.isnan(solzen))]
-    if len(solzen) == 0 or np.sum(solzen <= test_angle) < len(solzen):
+    if len(solzen) == 0 or np.sum(solzen >= test_angle) < len(solzen):
         return False
     else:
-        return True
+        return True
\ No newline at end of file