diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 005f3fa3c6..ec594f152b 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -12,7 +12,7 @@ jobs:
     vmImage: ubuntu-16.04
 
 
-- template: ci/azure/posix.yml
+- template: ci/azure/posix_no_39.yml
   parameters:
     name: Test_bare_macOS
     vmImage: macOS-10.14
diff --git a/ci/azure/posix_no_39.yml b/ci/azure/posix_no_39.yml
new file mode 100644
index 0000000000..16966cebef
--- /dev/null
+++ b/ci/azure/posix_no_39.yml
@@ -0,0 +1,39 @@
+parameters:
+  name: ''
+  vmImage: ''
+
+jobs:
+- job: ${{ parameters.name }}
+  pool:
+    vmImage: ${{ parameters.vmImage }}
+  strategy:
+    matrix:
+      Python36:
+        python.version: '3.6'
+      Python37:
+        python.version: '3.7'
+      Python38:
+        python.version: '3.8'
+
+  steps:
+  - task: UsePythonVersion@0
+    inputs:
+      versionSpec: '$(python.version)'
+
+  - script: |
+      pip install pytest pytest-cov pytest-mock requests-mock pytest-timeout pytest-azurepipelines pytest-rerunfailures pytest-remotedata
+      pip install -e .
+      pytest pvlib --junitxml=junit/test-results.xml --cov=com --cov-report=xml --cov-report=html
+    displayName: 'Test with pytest'
+
+  - task: PublishTestResults@2
+    condition: succeededOrFailed()
+    inputs:
+      testResultsFiles: '**/test-*.xml'
+      testRunTitle: 'Publish test results for Python $(python.version)'
+
+  - task: PublishCodeCoverageResults@1
+    inputs:
+      codeCoverageTool: Cobertura
+      summaryFileLocation: '$(System.DefaultWorkingDirectory)/**/coverage.xml'
+      reportDirectory: '$(System.DefaultWorkingDirectory)/**/htmlcov'
diff --git a/ci/requirements-py36-min.yml b/ci/requirements-py36-min.yml
index 84adcb360d..efcb166e68 100644
--- a/ci/requirements-py36-min.yml
+++ b/ci/requirements-py36-min.yml
@@ -5,6 +5,7 @@ dependencies:
     - coveralls
     - nose
     - pip
+    - pytables  # tables when using pip+PyPI
     - pytest
     - pytest-cov
     - pytest-mock
@@ -20,3 +21,4 @@ dependencies:
         - pytest-rerunfailures # conda version is >3.6
         - pytest-remotedata # conda package is 0.3.0, needs > 0.3.1
         - requests-mock
+        - numexpr==2.6.2 # needed for tables, but newest version is not compatible with numpy 1.12
\ No newline at end of file
diff --git a/ci/requirements-py36.yml b/ci/requirements-py36.yml
index c49455119f..9cef821b3b 100644
--- a/ci/requirements-py36.yml
+++ b/ci/requirements-py36.yml
@@ -3,6 +3,7 @@ channels:
     - defaults
     - conda-forge
 dependencies:
+    - blosc=1.14.3  # newest version breaks tables (pytables) on windows
     - coveralls
     - cython
     - ephem
diff --git a/ci/requirements-py37.yml b/ci/requirements-py37.yml
index 3203b004d1..598f2dcdf7 100644
--- a/ci/requirements-py37.yml
+++ b/ci/requirements-py37.yml
@@ -3,6 +3,7 @@ channels:
     - defaults
     - conda-forge
 dependencies:
+    - blosc=1.14.3  # newest version breaks tables (pytables) on windows
     - coveralls
     - cython
     - ephem
diff --git a/docs/sphinx/source/whatsnew/v0.9.0.rst b/docs/sphinx/source/whatsnew/v0.9.0.rst
index ed804160ac..f8d52e7e30 100644
--- a/docs/sphinx/source/whatsnew/v0.9.0.rst
+++ b/docs/sphinx/source/whatsnew/v0.9.0.rst
@@ -229,7 +229,8 @@ Documentation
 
 Requirements
 ~~~~~~~~~~~~
-* ``dataclasses`` is required for python 3.6
+* ``dataclasses`` is required for python 3.6 (:pull:`1076`)
+* ``tables`` is now required instead of optional (:issue:`1286`, :pull:`1287`)
 
 Contributors
 ~~~~~~~~~~~~
diff --git a/pvlib/clearsky.py b/pvlib/clearsky.py
index 9d635d0bf8..0368912c81 100644
--- a/pvlib/clearsky.py
+++ b/pvlib/clearsky.py
@@ -11,6 +11,7 @@
 import pandas as pd
 from scipy.optimize import minimize_scalar
 from scipy.linalg import hankel
+import tables
 
 from pvlib import atmosphere, tools
 
@@ -186,13 +187,6 @@ def lookup_linke_turbidity(time, latitude, longitude, filepath=None,
     # 1st row: 89.9583 S, 2nd row: 89.875 S
     # 1st column: 179.9583 W, 2nd column: 179.875 W
 
-    try:
-        import tables
-    except ImportError:
-        raise ImportError('The Linke turbidity lookup table requires tables. '
-                          'You can still use clearsky.ineichen if you '
-                          'supply your own turbidities.')
-
     if filepath is None:
         pvlib_path = os.path.dirname(os.path.abspath(__file__))
         filepath = os.path.join(pvlib_path, 'data', 'LinkeTurbidities.h5')
diff --git a/pvlib/tests/conftest.py b/pvlib/tests/conftest.py
index a3cba1e7b8..b3e9fcd5a1 100644
--- a/pvlib/tests/conftest.py
+++ b/pvlib/tests/conftest.py
@@ -105,15 +105,6 @@ def assert_frame_equal(left, right, **kwargs):
     not has_statsmodels, reason='requires statsmodels')
 
 
-try:
-    import tables
-    has_tables = True
-except ImportError:
-    has_tables = False
-
-requires_tables = pytest.mark.skipif(not has_tables, reason='requires tables')
-
-
 try:
     import ephem
     has_ephem = True
diff --git a/pvlib/tests/test_clearsky.py b/pvlib/tests/test_clearsky.py
index 1e7d89d82d..15fc74e383 100644
--- a/pvlib/tests/test_clearsky.py
+++ b/pvlib/tests/test_clearsky.py
@@ -16,7 +16,7 @@
 from pvlib import atmosphere
 from pvlib import irradiance
 
-from .conftest import requires_tables, DATA_DIR
+from .conftest import DATA_DIR
 
 
 def test_ineichen_series():
@@ -189,7 +189,6 @@ def test_ineichen_altitude():
     assert_frame_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity():
     times = pd.date_range(start='2014-06-24', end='2014-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -202,7 +201,6 @@ def test_lookup_linke_turbidity():
     assert_series_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity_leapyear():
     times = pd.date_range(start='2016-06-24', end='2016-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -215,7 +213,6 @@ def test_lookup_linke_turbidity_leapyear():
     assert_series_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity_nointerp():
     times = pd.date_range(start='2014-06-24', end='2014-06-25',
                           freq='12h', tz='America/Phoenix')
@@ -226,7 +223,6 @@ def test_lookup_linke_turbidity_nointerp():
     assert_series_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity_months():
     times = pd.date_range(start='2014-04-01', end='2014-07-01',
                           freq='1M', tz='America/Phoenix')
@@ -237,7 +233,6 @@ def test_lookup_linke_turbidity_months():
     assert_series_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity_months_leapyear():
     times = pd.date_range(start='2016-04-01', end='2016-07-01',
                           freq='1M', tz='America/Phoenix')
@@ -248,7 +243,6 @@ def test_lookup_linke_turbidity_months_leapyear():
     assert_series_equal(expected, out)
 
 
-@requires_tables
 def test_lookup_linke_turbidity_nointerp_months():
     times = pd.date_range(start='2014-04-10', end='2014-07-10',
                           freq='1M', tz='America/Phoenix')
@@ -480,7 +474,6 @@ def test_simplified_solis_nans_series():
     assert_frame_equal(expected, out)
 
 
-@requires_tables
 def test_linke_turbidity_corners():
     """Test Linke turbidity corners out of bounds."""
     months = pd.DatetimeIndex('%d/1/2016' % (m + 1) for m in range(12))
diff --git a/pvlib/tests/test_location.py b/pvlib/tests/test_location.py
index 20a849a667..a4b69e5cb2 100644
--- a/pvlib/tests/test_location.py
+++ b/pvlib/tests/test_location.py
@@ -15,7 +15,7 @@
 from pvlib.location import Location
 from pvlib.solarposition import declination_spencer71
 from pvlib.solarposition import equation_of_time_spencer71
-from .conftest import requires_ephem, requires_tables
+from .conftest import requires_ephem
 
 
 def test_location_required():
@@ -77,7 +77,6 @@ def times():
                          freq='3H')
 
 
-@requires_tables
 def test_get_clearsky(mocker, times):
     tus = Location(32.2, -111, 'US/Arizona', 700, 'Tucson')
     m = mocker.spy(pvlib.clearsky, 'ineichen')
diff --git a/pvlib/tests/test_modelchain.py b/pvlib/tests/test_modelchain.py
index 86b7411d0f..b42acfa54e 100644
--- a/pvlib/tests/test_modelchain.py
+++ b/pvlib/tests/test_modelchain.py
@@ -13,7 +13,7 @@
 from .conftest import assert_series_equal, assert_frame_equal
 import pytest
 
-from .conftest import fail_on_pvlib_version, requires_tables
+from .conftest import fail_on_pvlib_version
 
 
 @pytest.fixture(scope='function')
@@ -1788,7 +1788,6 @@ def test_ModelChain_attributes_deprecated_10(sapm_dc_snl_ac_system, location):
         mc.aoi = 5
 
 
-@requires_tables
 def test_basic_chain_alt_az(sam_data, cec_inverter_parameters,
                             sapm_temperature_cs5p_220m):
     times = pd.date_range(start='20160101 1200-0700',
@@ -1810,7 +1809,6 @@ def test_basic_chain_alt_az(sam_data, cec_inverter_parameters,
     assert_series_equal(ac, expected)
 
 
-@requires_tables
 def test_basic_chain_altitude_pressure(sam_data, cec_inverter_parameters,
                                        sapm_temperature_cs5p_220m):
     times = pd.date_range(start='20160101 1200-0700',
@@ -1861,7 +1859,6 @@ def test_complete_irradiance_clean_run(sapm_dc_snl_ac_system, location):
                         pd.Series([9, 5], index=times, name='ghi'))
 
 
-@requires_tables
 def test_complete_irradiance(sapm_dc_snl_ac_system, location):
     """Check calculations"""
     mc = ModelChain(sapm_dc_snl_ac_system, location)
@@ -1890,7 +1887,6 @@ def test_complete_irradiance(sapm_dc_snl_ac_system, location):
 
 @pytest.mark.filterwarnings("ignore:This function is not safe at the moment")
 @pytest.mark.parametrize("input_type", [tuple, list])
-@requires_tables
 def test_complete_irradiance_arrays(
         sapm_dc_snl_ac_system_same_arrays, location, input_type):
     """ModelChain.complete_irradiance can accept a tuple of weather
diff --git a/setup.py b/setup.py
index 216dc34a28..6dd1242744 100755
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,8 @@
                     'pandas >= 0.22.0',
                     'pytz',
                     'requests',
-                    'scipy >= 1.2.0']
+                    'scipy >= 1.2.0',
+                    'tables']
 
 # include dataclasses as a dependency only on python 3.6
 if sys.version_info.major == 3 and sys.version_info.minor == 6:
@@ -53,7 +54,7 @@
                  'pytest-remotedata']
 EXTRAS_REQUIRE = {
     'optional': ['cython', 'ephem', 'netcdf4', 'nrel-pysam', 'numba',
-                 'pvfactors', 'siphon', 'statsmodels', 'tables',
+                 'pvfactors', 'siphon', 'statsmodels',
                  'cftime >= 1.1.1'],
     'doc': ['ipython', 'matplotlib', 'sphinx == 3.1.2',
             'sphinx_rtd_theme==0.5.0', 'sphinx-gallery', 'docutils == 0.15.2',