diff --git a/poetry.lock b/poetry.lock
index bf1a92d..5ec2d0a 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -283,7 +283,7 @@ description = "The Cython compiler for writing C extensions for the Python langu
 name = "cython"
 optional = false
 python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
-version = "0.29.18"
+version = "0.29.20"
 
 [[package]]
 category = "main"
@@ -1840,7 +1840,7 @@ version = "2.0.0"
 heapdict = "*"
 
 [metadata]
-content-hash = "eece5e571eb71d4310e86954919e365f1cc4c4083958c72bef154a2fe45a5cfa"
+content-hash = "0057d3228afeb3859811dc66965b7a9b148d37c72bafb3383f8c1be9c11770c0"
 python-versions = "^3.8"
 
 [metadata.files]
@@ -1960,39 +1960,39 @@ cycler = [
     {file = "cycler-0.10.0.tar.gz", hash = "sha256:cd7b2d1018258d7247a71425e9f26463dfb444d411c39569972f4ce586b0c9d8"},
 ]
 cython = [
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+    {file = "Cython-0.29.20-py2.py3-none-any.whl", hash = "sha256:b56c02f14f1708411d95679962b742a1235d33a23535ce4a7f75425447701245"},
+    {file = "Cython-0.29.20.tar.gz", hash = "sha256:22d91af5fc2253f717a1b80b8bb45acb655f643611983fd6f782b9423f8171c7"},
 ]
 dask = [
     {file = "dask-2.18.0-py3-none-any.whl", hash = "sha256:e2b385cfa2b561b1ff003b19f4e4d1746f7273366ac06676e459191ebf66b768"},
diff --git a/pyproject.toml b/pyproject.toml
index 42d1de4..5691c3d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -7,7 +7,7 @@ license = "LGPL-3.0-or-later"
 
 [tool.poetry.dependencies]
 cartopy = "^0.18.0"
-cython = "^0.29.18"
+cython = "^0.29.20"
 dask = "^2.18.0"
 dask_labextension = "^2.0.2"
 datashader = "^0.11.0"