diff --git a/addons/resource/models/resource.py b/addons/resource/models/resource.py
index e590bdc0643..44d4c7babb9 100644
--- a/addons/resource/models/resource.py
+++ b/addons/resource/models/resource.py
@@ -3,7 +3,6 @@
 
 from collections import defaultdict
 import math
-import logging
 from datetime import datetime, time, timedelta
 from dateutil.relativedelta import relativedelta
 from dateutil.rrule import rrule, DAILY, WEEKLY
@@ -20,8 +19,6 @@ from odoo.tools.float_utils import float_round
 from odoo.tools import date_utils, float_utils
 from .resource_mixin import timezone_datetime
 
-_logger = logging.getLogger(__name__)
-
 # Default hour per day value. The one should
 # only be used when the one from the calendar
 # is not available.
@@ -475,15 +472,16 @@ class ResourceCalendar(models.Model):
         def interval_dt(interval):
             return interval[1 if match_end else 0]
 
+        if not dt.tzinfo or search_range and not (search_range[0].tzinfo and search_range[1].tzinfo):
+            raise ValueError('Provided datetimes needs to be timezoned')
+        dt = dt.astimezone(timezone(self.tz))
+
         if not search_range:
             range_start = dt + relativedelta(hour=0, minute=0, second=0)
             range_end = dt + relativedelta(days=1, hour=0, minute=0, second=0)
         else:
             range_start, range_end = search_range
 
-        if not (dt.tzinfo and range_start.tzinfo and range_end.tzinfo):
-            raise ValueError('Provided datetimes needs to be timezoned')
-
         if not range_start <= dt <= range_end:
             return None
         work_intervals = sorted(
@@ -778,7 +776,8 @@ class ResourceResource(models.Model):
         for resource in self:
             calendar_start = resource.calendar_id._get_closest_work_time(start, resource=resource)
             search_range = None
-            if calendar_start and start.date() == end.date():
+            tz = timezone(resource.tz)
+            if calendar_start and start.astimezone(tz).date() == end.astimezone(tz).date():
                 # Make sure to only search end after start
                 search_range = (
                     start,
diff --git a/addons/resource/tests/test_resource.py b/addons/resource/tests/test_resource.py
index 123648855be..280447adf57 100644
--- a/addons/resource/tests/test_resource.py
+++ b/addons/resource/tests/test_resource.py
@@ -438,6 +438,10 @@ class TestCalendar(TestResourceCommon):
         calendar_dt = self.calendar_john._get_closest_work_time(dt, resource=self.john.resource_id)
         self.assertEqual(calendar_dt, start, "It should have taken john's specific attendances")
 
+        dt = datetime_tz(2020, 4, 4, 1, 0, 0, tzinfo='UTC')  # The next day in UTC, but still the 3rd in john's timezone (America/Los_Angeles)
+        start = datetime_tz(2020, 4, 3, 16, 0, 0, tzinfo=self.john.tz)
+        calendar_dt = self.calendar_john._get_closest_work_time(dt, resource=self.john.resource_id)
+        self.assertEqual(calendar_dt, start, "It should have found the attendance on the 3rd April")
 
 class TestResMixin(TestResourceCommon):
 
@@ -487,6 +491,21 @@ class TestResMixin(TestResourceCommon):
             datetime_tz(2020, 4, 3, 13, 0, 0, tzinfo=self.john.tz),
         ))
 
+    def test_adjust_calendar_timezone_after(self):
+        # Calendar:
+        # Tuesdays 8-16
+        # Fridays 8-13 and 16-23
+        tz = 'Europe/Brussels'
+        self.john.tz = tz
+        result = self.john._adjust_to_calendar(
+            datetime(2020, 4, 2, 23, 0, 0),  # The previous day in UTC, but the 3rd in Europe/Brussels
+            datetime(2020, 4, 3, 20, 0, 0),
+        )
+        self.assertEqual(result[self.john], (
+            datetime(2020, 4, 3, 6, 0, 0),
+            datetime(2020, 4, 3, 21, 0, 0),
+        ), "It should have found a starting time the 3rd")
+
     def test_work_days_data(self):
         # Looking at Jean's calendar