diff --git a/addons/web/views/webclient_templates.xml b/addons/web/views/webclient_templates.xml
index deb37ef3f3c..23fd4e36e8a 100644
--- a/addons/web/views/webclient_templates.xml
+++ b/addons/web/views/webclient_templates.xml
@@ -464,6 +464,12 @@
         <xpath expr="//head/meta[last()]" position="after">
             <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no"/>
         </xpath>
+        <xpath expr="//head" position="inside">
+            <script type="text/javascript">
+                const userTZ = Intl.DateTimeFormat().resolvedOptions().timeZone;
+                document.cookie = `tz=${userTZ}; path=/`;
+            </script>
+        </xpath>
         <xpath expr="//head/link[last()]" position="after">
             <t t-call-assets="web.assets_common" t-js="false"/>
             <t t-call-assets="web.assets_frontend" t-js="false"/>
diff --git a/odoo/addons/base/models/res_users.py b/odoo/addons/base/models/res_users.py
index e9394d870e9..ab48d6270dd 100644
--- a/odoo/addons/base/models/res_users.py
+++ b/odoo/addons/base/models/res_users.py
@@ -643,6 +643,10 @@ class Users(models.Model):
                         raise AccessDenied()
                     user = user.with_user(user)
                     user._check_credentials(password)
+                    tz = request.httprequest.cookies.get('tz') if request else None
+                    if tz in pytz.all_timezones and (not user.tz or not user.login_date):
+                        # first login or missing tz -> set tz to browser tz
+                        user.tz = tz
                     user._update_last_login()
         except AccessDenied:
             _logger.info("Login failed for db:%s login:%s from %s", db, login, ip)