diff --git a/pyproject.toml b/pyproject.toml
index 027c3839..a33970e6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -30,10 +30,11 @@ dependencies = [
     "equinox @ git+https://github.com/patrick-kidger/equinox@1e601672d38d2c4d483535070a3572d8e8508a20",
     "PyYAML>=6.0.1",
     "xarray>=2023.12.0",
-    "netcdf4>=1.6.5",
+    "netcdf4>=1.6.5,<1.7.1",
     "h5netcdf>=1.3.0",
     "scipy>=1.12.0",
     "jaxtyping>=0.2.28",
+    "numpy<2.0.0",
 ]
 
 [project.urls]