diff --git a/.travis.yml b/.travis.yml
index 13c5362e530..6102381108a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -76,7 +76,7 @@ install:
   - python setup.py install
 
 script:
-  - py.test xarray --cov=xarray --cov-report term-missing --verbose
+  - py.test xarray --cov=xarray --cov-report term-missing --verbose --skip-slow
 
 after_success:
   - coveralls
diff --git a/appveyor.yml b/appveyor.yml
index 9f04ad8534c..9be28d583fc 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -38,4 +38,4 @@ install:
 build: false
 
 test_script:
-  - "py.test xarray --verbose"
+  - "py.test xarray --verbose --skip-slow"