diff --git a/src/anemoi/datasets/create/functions/sources/accumulations.py b/src/anemoi/datasets/create/functions/sources/accumulations.py
index 46a9e163c..fd87798ce 100644
--- a/src/anemoi/datasets/create/functions/sources/accumulations.py
+++ b/src/anemoi/datasets/create/functions/sources/accumulations.py
@@ -1,4 +1,4 @@
-# (C) Copyright 2024 Anemoi contributors.
+# (C) Copyright 2024-2025 Anemoi contributors.
 #
 # This software is licensed under the terms of the Apache Licence Version 2.0
 # which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
@@ -17,8 +17,6 @@
 from earthkit.data.core.temporary import temp_file
 from earthkit.data.readers.grib.output import new_grib_output
 
-from anemoi.datasets.create.utils import to_datetime_list
-
 from .mars import mars
 
 LOG = logging.getLogger(__name__)
@@ -32,7 +30,9 @@ def _member(field):
     return number
 
 
-class Accumulation:
+class RangeParameter:
+    buggy_steps = False
+
     def __init__(self, out, /, param, date, time, number, step, frequency, **kwargs):
         self.out = out
         self.param = param
@@ -85,10 +85,7 @@ def check(self, field):
     def write(self, template):
 
         assert self.startStep != self.endStep, (self.startStep, self.endStep)
-        if np.all(self.values < 0):
-            LOG.warning(
-                f"Negative values when computing accumutation for {self.param} ({self.date} {self.time}): min={np.amin(self.values)} max={np.amax(self.values)}"
-            )
+        self.check_results()
 
         self.out.write(
             self.values,
@@ -109,8 +106,7 @@ def add(self, field, values):
         if step not in self.steps:
             return
 
-        if not np.all(values >= 0):
-            warnings.warn(f"Negative values for {field}: {np.amin(values)} {np.amax(values)}")
+        self.check_values(field, values)
 
         assert not self.done, (self.key, step)
         assert step not in self.seen, (self.key, step)
@@ -154,6 +150,24 @@ def mars_date_time_steps(cls, dates, step1, step2, frequency, base_times, adjust
     def __repr__(self) -> str:
         return f"{self.__class__.__name__}({self.key})"
 
+    def check_values(self, field, values):
+        pass
+
+    def check_results(self):
+        pass
+
+
+class Accumulation(RangeParameter):
+    def check_values(self, field, values):
+        if not np.all(values >= 0):
+            warnings.warn(f"Negative values for {field}: {np.amin(values)} {np.amax(values)}")
+
+    def check_results(self):
+        if np.all(self.values < 0):
+            LOG.warning(
+                f"Negative values when computing accumutation for {self.param} ({self.date} {self.time}): min={np.amin(self.values)} max={np.amax(self.values)}"
+            )
+
 
 class AccumulationFromStart(Accumulation):
     buggy_steps = True
@@ -201,7 +215,6 @@ def _mars_date_time_step(cls, base_date, step1, step2, add_step, frequency):
 
 
 class AccumulationFromLastStep(Accumulation):
-    buggy_steps = False
 
     def compute(self, values, startStep, endStep):
 
@@ -241,11 +254,66 @@ def _mars_date_time_step(cls, base_date, step1, step2, add_step, frequency):
         )
 
 
+class Operation(RangeParameter):
+
+    def compute(self, values, startStep, endStep):
+
+        assert endStep - startStep == self.frequency, (
+            startStep,
+            endStep,
+            self.frequency,
+        )
+
+        if self.startStep is None:
+            self.startStep = startStep
+        else:
+            self.startStep = min(self.startStep, startStep)
+
+        if self.endStep is None:
+            self.endStep = endStep
+        else:
+            self.endStep = max(self.endStep, endStep)
+
+        if self.values is None:
+            self.values = values.copy()
+
+        self.values = self.operation(self.values, values)
+
+    @classmethod
+    def _mars_date_time_step(cls, base_date, step1, step2, add_step, frequency):
+        assert frequency > 0, frequency
+        # assert step1 > 0, (step1, step2, frequency, add_step, base_date)
+
+        steps = []
+        for step in range(step1 + frequency, step2 + frequency, frequency):
+            steps.append(step + add_step)
+        return (
+            base_date.year * 10000 + base_date.month * 100 + base_date.day,
+            base_date.hour * 100 + base_date.minute,
+            tuple(steps),
+        )
+
+
+class Maximum(Operation):
+    operation = np.maximum
+
+
+class Mininmum(Operation):
+    operation = np.minimum
+
+
 def _identity(x):
     return x
 
 
-def _compute_accumulations(
+OPERATIONS = {
+    "accumulation": Accumulation,
+    "minimum": Mininmum,
+    "maximum": Maximum,
+}
+
+
+def _compute_range_parameter(
     context,
     dates,
     request,
@@ -254,6 +322,7 @@ def _compute_accumulations(
     patch=_identity,
     base_times=None,
     use_cdsapi_dataset=None,
+    operation="accumulation",
 ):
     adjust_step = isinstance(user_accumulation_period, int)
 
@@ -269,9 +338,14 @@ def _compute_accumulations(
 
     base_times = [t // 100 if t > 100 else t for t in base_times]
 
-    AccumulationClass = AccumulationFromStart if data_accumulation_period in (0, None) else AccumulationFromLastStep
+    if operation == "accumulation":
+        RangeParameterClass = (
+            AccumulationFromStart if data_accumulation_period in (0, None) else AccumulationFromLastStep
+        )
+    else:
+        RangeParameterClass = OPERATIONS[operation]
 
-    mars_date_time_steps = AccumulationClass.mars_date_time_steps(
+    mars_date_time_steps = RangeParameterClass.mars_date_time_steps(
         dates,
         step1,
         step2,
@@ -317,7 +391,7 @@ def _compute_accumulations(
     )
 
     accumulations = {}
-    for a in [AccumulationClass(out, frequency=frequency, **r) for r in requests]:
+    for a in [RangeParameterClass(out, frequency=frequency, **r) for r in requests]:
         for s in a.steps:
             key = (a.param, a.date, a.time, s, a.number)
             accumulations.setdefault(key, []).append(a)
@@ -369,7 +443,7 @@ def _scda(request):
     return request
 
 
-def accumulations(context, dates, use_cdsapi_dataset=None, **request):
+def range_parameter(context, dates, operation, use_cdsapi_dataset=None, **request):
     _to_list(request["param"])
     class_ = request.get("class", "od")
     stream = request.get("stream", "oper")
@@ -391,37 +465,21 @@ def accumulations(context, dates, use_cdsapi_dataset=None, **request):
 
     kwargs = KWARGS.get((class_, stream), {})
 
-    context.trace("🌧️", f"accumulations {request} {user_accumulation_period} {kwargs}")
+    context.trace("🌧️", f"{operation} {request} {user_accumulation_period} {kwargs}")
 
-    return _compute_accumulations(
+    return _compute_range_parameter(
         context,
         dates,
         request,
+        operation=operation,
         user_accumulation_period=user_accumulation_period,
         use_cdsapi_dataset=use_cdsapi_dataset,
         **kwargs,
     )
 
 
-execute = accumulations
+def accumulations(context, dates, use_cdsapi_dataset=None, **request):
+    return range_parameter(context, dates, "accumulation", use_cdsapi_dataset=use_cdsapi_dataset, **request)
 
-if __name__ == "__main__":
-    import yaml
-
-    config = yaml.safe_load(
-        """
-      class: ea
-      expver: '0001'
-      grid: 20./20.
-      levtype: sfc
-#      number: [0, 1]
-#      stream: enda
-      param: [cp, tp]
-#      accumulation_period: 6h
-    """
-    )
-    dates = yaml.safe_load("[2022-12-30 18:00, 2022-12-31 00:00, 2022-12-31 06:00, 2022-12-31 12:00]")
-    dates = to_datetime_list(dates)
 
-    for f in accumulations(None, dates, **config):
-        print(f, f.to_numpy().mean())
+execute = accumulations
diff --git a/src/anemoi/datasets/create/functions/sources/maximum_since_previous_step.py b/src/anemoi/datasets/create/functions/sources/maximum_since_previous_step.py
new file mode 100644
index 000000000..14834dbf7
--- /dev/null
+++ b/src/anemoi/datasets/create/functions/sources/maximum_since_previous_step.py
@@ -0,0 +1,18 @@
+# (C) Copyright 2025 Anemoi contributors.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+
+import logging
+
+from .accumulations import range_parameter
+
+LOG = logging.getLogger(__name__)
+
+
+def execute(context, dates, use_cdsapi_dataset=None, **request):
+    return range_parameter(context, dates, "maximum", use_cdsapi_dataset=use_cdsapi_dataset, **request)
diff --git a/src/anemoi/datasets/create/functions/sources/minimum_since_previous_step.py b/src/anemoi/datasets/create/functions/sources/minimum_since_previous_step.py
new file mode 100644
index 000000000..0b1f99554
--- /dev/null
+++ b/src/anemoi/datasets/create/functions/sources/minimum_since_previous_step.py
@@ -0,0 +1,18 @@
+# (C) Copyright 2025 Anemoi contributors.
+#
+# This software is licensed under the terms of the Apache Licence Version 2.0
+# which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# In applying this licence, ECMWF does not waive the privileges and immunities
+# granted to it by virtue of its status as an intergovernmental organisation
+# nor does it submit to any jurisdiction.
+
+import logging
+
+from .accumulations import range_parameter
+
+LOG = logging.getLogger(__name__)
+
+
+def execute(context, dates, use_cdsapi_dataset=None, **request):
+    return range_parameter(context, dates, "minimum", use_cdsapi_dataset=use_cdsapi_dataset, **request)