diff --git a/ci/requirements/docs.yml b/ci/requirements/docs.yml
index d72256738..e0043da2d 100644
--- a/ci/requirements/docs.yml
+++ b/ci/requirements/docs.yml
@@ -29,7 +29,7 @@ dependencies:
   - importlib-metadata <8.0.0 # Pin needed for esmpy compatibility. See: https://github.com/pangeo-data/xESMF/issues/374
   - nc-time-axis >=1.4.0
   - numba >=0.52
-  - numpy >=1.25.0
+  - numpy >=1.25.0,<2.0.0  # Pin below v2.0.0 until xclim supports it.
   - xclim
   - xesmf
   - xrft
diff --git a/ci/requirements/maximum-tests.yml b/ci/requirements/maximum-tests.yml
index cbd66f83d..3964f510f 100644
--- a/ci/requirements/maximum-tests.yml
+++ b/ci/requirements/maximum-tests.yml
@@ -11,10 +11,10 @@ dependencies:
   - eofs
   # - esmpy =*=mpi*  # Ensures MPI works with version of esmpy. # Commented out for CI testing.
   - h5netcdf
-  - importlib-metadata <8.0.0 # Pin needed for esmpy compatibility. See: https://github.com/pangeo-data/xESMF/issues/374
+  - importlib-metadata <8.0.0  # Pin needed for esmpy compatibility. See: https://github.com/pangeo-data/xESMF/issues/374
   - matplotlib-base
   - nc-time-axis >=1.4.0
-  - numpy >=1.25.0
+  - numpy >=1.25.0,<2.0.0  # Pin below v2.0.0 until xclim supports it.
   - pip
   - pooch
   - pytest <8.0.0
diff --git a/pyproject.toml b/pyproject.toml
index e21bc190d..2d9c6391c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,7 +47,7 @@ dynamic = ["version", "description"]
 
 [project.optional-dependencies]
 accel = ["numba >=0.52", "bottleneck"]
-bias-correction = ["xclim >=0.46", "bias-correction >=0.4"]
+bias-correction = ["xclim >=0.46", "bias-correction >=0.4", "numpy >=1.25.0,<2.0.0"] # pinned until xclim supports numpy>=2.0.0
 io = ["netcdf4"] # use h5netcdf when encountering seg faults as in GitHub Actions CI
 regridding = ["xesmf"] # for installation see https://pangeo-xesmf.readthedocs.io/
 relative_entropy = ["eofs"]