diff --git a/pkgs/development/python-modules/cython_test.patch b/pkgs/development/python-modules/cython_test.patch
deleted file mode 100644
index 5b1cece3aa50..000000000000
--- a/pkgs/development/python-modules/cython_test.patch
+++ /dev/null
@@ -1,15 +0,0 @@
-diff --git a/tests/run/numpy_math.pyx b/tests/run/numpy_math.pyx
-index eafd23a..4a15522 100644
---- a/tests/run/numpy_math.pyx
-+++ b/tests/run/numpy_math.pyx
-@@ -37,8 +37,8 @@ def test_fp_classif():
-     assert not npmath.isnan(d_zero)
-     assert not npmath.isnan(f_zero)
- 
--    assert npmath.isinf(npmath.INFINITY) == 1
--    assert npmath.isinf(-npmath.INFINITY) == -1
-+    assert npmath.isinf(npmath.INFINITY) != 0
-+    assert npmath.isinf(-npmath.INFINITY) != 0
-     assert npmath.isnan(npmath.NAN)
- 
-     assert npmath.signbit(npmath.copysign(1., -1.))
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 31724a1597d4..7e8ce52c66bc 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -4233,20 +4233,18 @@ in {
 
   cython = buildPythonPackage rec {
     name = "Cython-${version}";
-    version = "0.24.1";
+    version = "0.25.1";
 
     src = pkgs.fetchurl {
       url = "mirror://pypi/C/Cython/${name}.tar.gz";
-      sha256 = "84808fda00508757928e1feadcf41c9f78e9a9b7167b6649ab0933b76f75e7b9";
+      sha256 = "e0941455769335ec5afb17dee36dc3833b7edc2ae20a8ed5806c58215e4b6669";
     };
 
-    buildInputs = with self; [ pkgs.pkgconfig pkgs.gdb ];
+    buildInputs = with self; [ pkgs.glibcLocales pkgs.pkgconfig pkgs.gdb ];
     # For testing
     nativeBuildInputs = with self; [ numpy pkgs.ncurses ];
 
-    # cython's testsuite requires npy_isinf to return sign of the infinity, but
-    # a C99 conformant is only required to return a non zero value
-    patches = [ ../development/python-modules/cython_test.patch ];
+    LC_ALL = "en_US.UTF-8";
 
     # cython's testsuite is not working very well with libc++
     # We are however optimistic about things outside of testsuite still working