diff --git a/cara/apps/calculator/model_generator.py b/cara/apps/calculator/model_generator.py
index 1d4f51ec..4baddaf7 100644
--- a/cara/apps/calculator/model_generator.py
+++ b/cara/apps/calculator/model_generator.py
@@ -22,7 +22,7 @@ minutes_since_midnight = typing.NewType('minutes_since_midnight', int)
 # Used to declare when an attribute of a class must have a value provided, and
 # there should be no default value used.
 _NO_DEFAULT = object()
-_SAMPLE_SIZE = 50000
+_SAMPLE_SIZE = 10000
 
 @dataclass
 class FormData:
diff --git a/cara/data.py b/cara/data.py
index f84e627e..61f103b9 100644
--- a/cara/data.py
+++ b/cara/data.py
@@ -38,7 +38,7 @@ GenevaTemperatures_hourly = {
 }
 # same temperatures on a finer temperature mesh
 GenevaTemperatures = {
-    month: GenevaTemperatures_hourly[month].refine(refine_factor=10)
+    month: GenevaTemperatures_hourly[month].refine(refine_factor=4)
     for month,temperatures in Geneva_hourly_temperatures_celsius_per_hour.items()
 }