diff --git a/pyaerocom/_lowlevel_helpers.py b/pyaerocom/_lowlevel_helpers.py
index 4e25f5438..00798847a 100644
--- a/pyaerocom/_lowlevel_helpers.py
+++ b/pyaerocom/_lowlevel_helpers.py
@@ -9,6 +9,7 @@
 from pathlib import Path
 
 import numpy as np
+from typing_extensions import TypedDict
 
 from pyaerocom._warnings import ignore_warnings
 
@@ -704,3 +705,10 @@ def str_underline(title: str, indent: int = 0):
     length = indent + len(title)
     underline = "-" * len(title)
     return f"{title:>{length}}\n{underline:>{length}}"
+
+
+class RegridResDeg(TypedDict):
+    """Typed dict for regridding resolution degrees"""
+
+    lat_res_deg: float
+    lon_res_deg: float
diff --git a/pyaerocom/colocation/colocation_3d.py b/pyaerocom/colocation/colocation_3d.py
index 9af4a85fc..853e35d4d 100644
--- a/pyaerocom/colocation/colocation_3d.py
+++ b/pyaerocom/colocation/colocation_3d.py
@@ -14,6 +14,7 @@
 
 from pyaerocom import __version__ as pya_ver
 from pyaerocom import const
+from pyaerocom._lowlevel_helpers import RegridResDeg
 from pyaerocom.exceptions import (
     DataUnitError,
     DimensionOrderError,
@@ -303,7 +304,7 @@ def colocate_vertical_profile_gridded(
     start: str | None = None,
     stop: str | None = None,
     filter_name: str = None,
-    regrid_res_deg: int | dict | None = None,
+    regrid_res_deg: float | RegridResDeg | None = None,
     harmonise_units: bool = True,
     regrid_scheme: str = "areaweighted",
     var_ref: str = None,
diff --git a/pyaerocom/colocation/colocation_setup.py b/pyaerocom/colocation/colocation_setup.py
index b22682db6..538f700c8 100644
--- a/pyaerocom/colocation/colocation_setup.py
+++ b/pyaerocom/colocation/colocation_setup.py
@@ -16,6 +16,7 @@
 )
 
 from pyaerocom import const
+from pyaerocom._lowlevel_helpers import RegridResDeg
 from pyaerocom.config import ALL_REGION_NAME
 from pyaerocom.helpers import start_stop
 from pyaerocom.io.pyaro.pyaro_config import PyaroConfig
@@ -257,9 +258,12 @@ class ColocationSetup(BaseModel):
     harmonise_units : bool
         if True, units are attempted to be harmonised during co-location
         (note: raises Exception if True and in case units cannot be harmonised).
-    regrid_res_deg : int, optional
-        resolution in degrees for regridding of model grid (done before
-        co-location). Default is None.
+    regrid_res_deg : float or dict, optional
+        regrid resolution in degrees. If specified, the input gridded data
+        objects will be regridded in lon / lat dimension to the input
+        resolution (if input is float, both lat and lon are regridded to that
+        resolution, if input is dict, use keys `lat_res_deg` and `lon_res_deg`
+        to specify regrid resolutions, respectively). Default is None.
     colocate_time : bool
         if True and if obs and model sampling frequency (e.g. daily) are higher
         than output colocation frequency (e.g. monthly), then the datasets are
@@ -411,7 +415,7 @@ def validate_basedirs(cls, v):
     model_outlier_ranges: dict[str, tuple[float, float]] | None = {}
     zeros_to_nan: bool = False
     harmonise_units: bool = False
-    regrid_res_deg: float | None = None
+    regrid_res_deg: float | RegridResDeg | None = None
     colocate_time: bool = False
     reanalyse_existing: bool = True
     raise_exceptions: bool = False
diff --git a/pyaerocom/colocation/colocation_utils.py b/pyaerocom/colocation/colocation_utils.py
index bd35fbb0d..7ef83f3ed 100644
--- a/pyaerocom/colocation/colocation_utils.py
+++ b/pyaerocom/colocation/colocation_utils.py
@@ -12,6 +12,7 @@
 
 from pyaerocom import __version__ as pya_ver
 from pyaerocom import const
+from pyaerocom._lowlevel_helpers import RegridResDeg
 from pyaerocom.exceptions import (
     DataUnitError,
     DimensionOrderError,
@@ -69,7 +70,7 @@ def resolve_var_name(data):
     return (var, vardef.var_name_aerocom)
 
 
-def _regrid_gridded(gridded, regrid_scheme, regrid_res_deg):
+def _regrid_gridded(gridded, regrid_scheme: str, regrid_res_deg: RegridResDeg):
     """
     Regrid instance of `GriddedData`
 
@@ -99,7 +100,7 @@ def _regrid_gridded(gridded, regrid_scheme, regrid_res_deg):
         regridded data object
 
     """
-    if not isinstance(regrid_res_deg, dict):
+    if not isinstance(regrid_res_deg, dict):  # at runtime RegridResDeg is a dict
         if not isnumeric(regrid_res_deg):
             raise ValueError(
                 "Invalid input for regrid_res_deg. Need integer "
@@ -158,9 +159,9 @@ def colocate_gridded_gridded(
     start=None,
     stop=None,
     filter_name=None,
-    regrid_res_deg=None,
+    regrid_res_deg: float | RegridResDeg | None = None,
     harmonise_units=True,
-    regrid_scheme="areaweighted",
+    regrid_scheme: str = "areaweighted",
     update_baseyear_gridded=None,
     min_num_obs=None,
     colocate_time=False,
@@ -580,9 +581,9 @@ def colocate_gridded_ungridded(
     start=None,
     stop=None,
     filter_name=None,
-    regrid_res_deg=None,
+    regrid_res_deg: float | RegridResDeg | None = None,
     harmonise_units=True,
-    regrid_scheme="areaweighted",
+    regrid_scheme: str = "areaweighted",
     var_ref=None,
     update_baseyear_gridded=None,
     min_num_obs=None,