diff --git a/app/assets/js/setTimezone.js b/app/assets/js/setTimezone.js
new file mode 100644
index 0000000000..5a79b0190e
--- /dev/null
+++ b/app/assets/js/setTimezone.js
@@ -0,0 +1,4 @@
+document.addEventListener('DOMContentLoaded', function() {
+    var timeZone = Intl.DateTimeFormat().resolvedOptions().timeZone;
+    document.cookie = `timezone=${timeZone}; path=/`;
+})
diff --git a/app/main/views/dashboard.py b/app/main/views/dashboard.py
index 0913dcfdda..ee289c3e5d 100644
--- a/app/main/views/dashboard.py
+++ b/app/main/views/dashboard.py
@@ -16,6 +16,7 @@
 )
 from app.formatters import format_date_numeric, format_datetime_numeric, get_time_left
 from app.main import main
+from app.main.views.user_profile import set_timezone
 from app.statistics_utils import get_formatted_percentage
 from app.utils import (
     DELIVERED_STATUSES,
@@ -39,6 +40,7 @@ def old_service_dashboard(service_id):
 @main.route("/services/<uuid:service_id>")
 @user_has_permissions()
 def service_dashboard(service_id):
+
     if session.get("invited_user_id"):
         session.pop("invited_user_id", None)
         session["service_id"] = service_id
@@ -402,11 +404,13 @@ def get_dashboard_partials(service_id):
 
 
 def get_dashboard_totals(statistics):
+
     for msg_type in statistics.values():
         msg_type["failed_percentage"] = get_formatted_percentage(
             msg_type["failed"], msg_type["requested"]
         )
         msg_type["show_warning"] = float(msg_type["failed_percentage"]) > 3
+
     return statistics
 
 
@@ -465,6 +469,8 @@ def get_months_for_financial_year(year, time_format="%B"):
 
 
 def get_current_month_for_financial_year(year):
+    # Setting the timezone here because we need to set it somewhere.
+    set_timezone()
     current_month = datetime.now().month
     return current_month
 
diff --git a/app/main/views/send.py b/app/main/views/send.py
index 6f2817826f..e6843da18d 100644
--- a/app/main/views/send.py
+++ b/app/main/views/send.py
@@ -33,6 +33,7 @@
     SetSenderForm,
     get_placeholder_form_instance,
 )
+from app.main.views.user_profile import set_timezone
 from app.models.user import Users
 from app.s3_client.s3_csv_client import (
     get_csv_metadata,
@@ -1075,6 +1076,7 @@ def get_spreadsheet_column_headings_from_template(template):
 
 
 def get_recipient():
+    set_timezone()
     if {"recipient", "placeholders"} - set(session.keys()):
         return None
 
diff --git a/app/main/views/user_profile.py b/app/main/views/user_profile.py
index 2efac8b236..ec9e27035f 100644
--- a/app/main/views/user_profile.py
+++ b/app/main/views/user_profile.py
@@ -29,6 +29,7 @@
     TwoFactorForm,
 )
 from app.models.user import User
+from app.utils import hilite
 from app.utils.user import user_is_gov_user, user_is_logged_in
 from notifications_utils.url_safe_token import check_token
 
@@ -275,3 +276,15 @@ def user_profile_disable_platform_admin_view():
     return render_template(
         "views/user-profile/disable-platform-admin-view.html", form=form
     )
+
+
+def set_timezone():
+    # Cookie is set in dashboard.html on page load
+    try:
+        timezone = request.cookies.get("timezone", "US/Eastern")
+        current_app.logger.debug(hilite(f"User's timezone is {timezone}"))
+        serialized_user = current_user.serialize()
+        if serialized_user["preferred_timezone"] is not timezone:
+            current_user.update(preferred_timezone=timezone)
+    except Exception:
+        current_app.logger.exception(hilite("Can't get timezone"))
diff --git a/app/models/user.py b/app/models/user.py
index 3c96fc42c4..6991dc035b 100644
--- a/app/models/user.py
+++ b/app/models/user.py
@@ -58,6 +58,7 @@ def __init__(self, _dict):
         super().__init__(_dict)
         self.permissions = _dict.get("permissions", {})
         self._platform_admin = _dict["platform_admin"]
+        self.preferred_timezone = _dict.get("preferred_timezone", "America/New_York")
 
     @classmethod
     def from_id(cls, user_id):
diff --git a/app/templates/views/dashboard/dashboard.html b/app/templates/views/dashboard/dashboard.html
index 3ea625bb37..9268b37e33 100644
--- a/app/templates/views/dashboard/dashboard.html
+++ b/app/templates/views/dashboard/dashboard.html
@@ -1,3 +1,5 @@
+
+
 {% extends "withnav_template.html" %}
 
 {% from "components/table.html" import list_table, field, text_field, link_field, right_aligned_field_heading, hidden_field_heading, row_heading, notification_status_field, notification_carrier_field, notification_carrier_message_field %}
@@ -8,6 +10,8 @@
 {% endblock %}
 
 {% block maincolumn_content %}
+  <script type="text/javascript" src="{{ asset_url('js/setTimezone.js') }}"></script>
+
 
   <div class="dashboard margin-bottom-2">
 
diff --git a/app/templates/views/send.html b/app/templates/views/send.html
index 8685f81968..b8a0c65610 100644
--- a/app/templates/views/send.html
+++ b/app/templates/views/send.html
@@ -4,6 +4,7 @@
 {% from "components/file-upload.html" import file_upload %}
 {% from "components/table.html" import list_table, text_field, index_field, index_field_heading %}
 {% from "components/components/back-link/macro.njk" import usaBackLink %}
+<script type="text/javascript" src="{{ asset_url('js/setTimezone.js') }}"></script>
 
 {% block service_page_title %}
   Upload a list of {{ 999|recipient_count_label(template.template_type) }}
diff --git a/app/templates/views/user-profile.html b/app/templates/views/user-profile.html
index 6f243d7a82..246444d5a1 100644
--- a/app/templates/views/user-profile.html
+++ b/app/templates/views/user-profile.html
@@ -45,14 +45,9 @@ <h1 class="font-body-2xl margin-bottom-3">User profile</h1>
       {% endcall %}
 
       {% call row() %}
-        {{ text_field('Preferred Timezone') }}
+        {{ text_field('Preferred timezone') }}
         {{ optional_text_field(current_user.preferred_timezone) }}
-        {{ edit_field(
-            'Change',
-            url_for('.user_profile_preferred_timezone'),
-            suffix='preferred timezone'
-          )
-        }}
+        {{ text_field('Set automatically') }}
       {% endcall %}
 
       {% if current_user.platform_admin or session.get('disable_platform_admin_view') %}
diff --git a/gulpfile.js b/gulpfile.js
index d4d6ac81f4..4d2571eaec 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -97,6 +97,13 @@ const copyGtmHead = () => {
     .pipe(dest(paths.dist + 'js/'));
 };
 
+// Task to copy `setTimezone.js`
+const copySetTimezone = () => {
+  return src(paths.src + 'js/setTimezone.js')
+    .pipe(dest(paths.dist + 'js/'));
+};
+
+
 // Task to copy images
 const copyImages = () => {
   return src(paths.src + 'images/**/*', { encoding: false })
@@ -122,4 +129,4 @@ const copyAssets = async () => {
   await uswds.copyAssets();
 };
 
-exports.default = series(styles, javascripts, copyGtmHead, copyImages, copyAssets);
+exports.default = series(styles, javascripts, copyGtmHead, copySetTimezone, copyImages, copyAssets);
diff --git a/poetry.lock b/poetry.lock
index 4cc5704710..2684ecc215 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -2433,7 +2433,6 @@ files = [
     {file = "PyYAML-6.0.1-cp311-cp311-win_amd64.whl", hash = "sha256:bf07ee2fef7014951eeb99f56f39c9bb4af143d8aa3c21b1677805985307da34"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:855fb52b0dc35af121542a76b9a84f8d1cd886ea97c84703eaa6d88e37a2ad28"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:40df9b996c2b73138957fe23a16a4f0ba614f4c0efce1e9406a184b6d07fa3a9"},
-    {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a08c6f0fe150303c1c6b71ebcd7213c2858041a7e01975da3a99aed1e7a378ef"},
     {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:6c22bec3fbe2524cde73d7ada88f6566758a8f7227bfbf93a408a9d86bcc12a0"},
     {file = "PyYAML-6.0.1-cp312-cp312-musllinux_1_1_x86_64.whl", hash = "sha256:8d4e9c88387b0f5c7d5f281e55304de64cf7f9c0021a3525bd3b1c542da3b0e4"},
     {file = "PyYAML-6.0.1-cp312-cp312-win32.whl", hash = "sha256:d483d2cdf104e7c9fa60c544d92981f12ad66a457afae824d146093b8c294c54"},
diff --git a/tests/app/main/views/test_conversation.py b/tests/app/main/views/test_conversation.py
index 1139cd43f8..15a5ec587c 100644
--- a/tests/app/main/views/test_conversation.py
+++ b/tests/app/main/views/test_conversation.py
@@ -113,55 +113,55 @@ def test_view_conversation(
         [
             (
                 "message-8",
-                "yesterday at 14:59 US/Eastern",
+                "yesterday at 14:59 America/New_York",
             ),
             (
                 "message-7",
-                "yesterday at 14:59 US/Eastern",
+                "yesterday at 14:59 America/New_York",
             ),
             (
                 "message-6",
-                "yesterday at 16:59 US/Eastern",
+                "yesterday at 16:59 America/New_York",
             ),
             (
                 "message-5",
-                "yesterday at 18:59 US/Eastern",
+                "yesterday at 18:59 America/New_York",
             ),
             (
                 "message-4",
-                "yesterday at 20:59 US/Eastern",
+                "yesterday at 20:59 America/New_York",
             ),
             (
                 "message-3",
-                "yesterday at 22:59 US/Eastern",
+                "yesterday at 22:59 America/New_York",
             ),
             (
                 "message-2",
-                "yesterday at 22:59 US/Eastern",
+                "yesterday at 22:59 America/New_York",
             ),
             (
                 "message-1",
-                "yesterday at 23:00 US/Eastern",
+                "yesterday at 23:00 America/New_York",
             ),
             (
                 expected_outbound_content,
-                "yesterday at 00:00 US/Eastern",
+                "yesterday at 00:00 America/New_York",
             ),
             (
                 expected_outbound_content,
-                "yesterday at 00:00 US/Eastern",
+                "yesterday at 00:00 America/New_York",
             ),
             (
                 expected_outbound_content,
-                "yesterday at 00:00 US/Eastern",
+                "yesterday at 00:00 America/New_York",
             ),
             (
                 expected_outbound_content,
-                "yesterday at 00:00 US/Eastern",
+                "yesterday at 00:00 America/New_York",
             ),
             (
                 expected_outbound_content,
-                "yesterday at 00:00 US/Eastern",
+                "yesterday at 00:00 America/New_York",
             ),
         ]
     ):
diff --git a/tests/app/main/views/test_dashboard.py b/tests/app/main/views/test_dashboard.py
index d5bab63232..e2a7a6b587 100644
--- a/tests/app/main/views/test_dashboard.py
+++ b/tests/app/main/views/test_dashboard.py
@@ -550,14 +550,14 @@ def test_download_inbox(
     )
     assert response.get_data(as_text=True) == (
         "Phone number,Message,Received\r\n"
-        "(202) 867-5300,message-1,07-01-2016 11:00 US/Eastern\r\n"
-        "(202) 867-5300,message-2,07-01-2016 10:59 US/Eastern\r\n"
-        "(202) 867-5300,message-3,07-01-2016 10:59 US/Eastern\r\n"
-        "(202) 867-5302,message-4,07-01-2016 08:59 US/Eastern\r\n"
-        "+33(0)1 12345678,message-5,07-01-2016 06:59 US/Eastern\r\n"
-        "(202) 555-0104,message-6,07-01-2016 04:59 US/Eastern\r\n"
-        "(202) 555-0104,message-7,07-01-2016 02:59 US/Eastern\r\n"
-        "+68212345,message-8,07-01-2016 02:59 US/Eastern\r\n"
+        "(202) 867-5300,message-1,07-01-2016 11:00 America/New_York\r\n"
+        "(202) 867-5300,message-2,07-01-2016 10:59 America/New_York\r\n"
+        "(202) 867-5300,message-3,07-01-2016 10:59 America/New_York\r\n"
+        "(202) 867-5302,message-4,07-01-2016 08:59 America/New_York\r\n"
+        "+33(0)1 12345678,message-5,07-01-2016 06:59 America/New_York\r\n"
+        "(202) 555-0104,message-6,07-01-2016 04:59 America/New_York\r\n"
+        "(202) 555-0104,message-7,07-01-2016 02:59 America/New_York\r\n"
+        "+68212345,message-8,07-01-2016 02:59 America/New_York\r\n"
     )
 
 
@@ -849,7 +849,7 @@ def test_should_show_upcoming_jobs_on_dashboard(
     assert normalize_spaces(page.select_one("main h2").text) == ("In the next few days")
 
     assert normalize_spaces(page.select_one("a.banner-dashboard").text) == (
-        "2 files waiting to send " "- sending starts today at 06:09 US/Eastern"
+        "2 files waiting to send " "- sending starts today at 06:09 America/New_York"
     )
 
     assert page.select_one("a.banner-dashboard")["href"] == url_for(
@@ -1786,7 +1786,6 @@ def test_org_breadcrumbs_show_if_user_is_platform_admin(
 
     client_request.login(platform_admin_user, service_one_json)
     page = client_request.get("main.service_dashboard", service_id=SERVICE_ONE_ID)
-
     assert page.select_one(".navigation-organization-link")["href"] == url_for(
         "main.organization_dashboard",
         org_id=ORGANISATION_ID,
diff --git a/tests/app/main/views/test_jobs.py b/tests/app/main/views/test_jobs.py
index c4a7561946..ab09f7ecd8 100644
--- a/tests/app/main/views/test_jobs.py
+++ b/tests/app/main/views/test_jobs.py
@@ -349,7 +349,7 @@ def test_should_show_scheduled_job(
     )
 
     assert normalize_spaces(page.select("main div p")[1].text) == (
-        "Example template - service one was scheduled on January 02, 2016 at 12:00 AM US/Eastern by Test User"
+        "Example template - service one was scheduled on January 02, 2016 at 12:00 AM America/New_York by Test User"
     )
 
     assert page.select("main p a")[0]["href"] == url_for(
diff --git a/tests/app/main/views/test_templates.py b/tests/app/main/views/test_templates.py
index b23caf925b..6e2ff227de 100644
--- a/tests/app/main/views/test_templates.py
+++ b/tests/app/main/views/test_templates.py
@@ -497,7 +497,7 @@ def test_caseworker_sees_template_page_if_template_is_deleted(
     )
     assert (
         page.select("p.hint")[0].text.strip()
-        == "This template was deleted today at 15:00 US/Eastern."
+        == "This template was deleted today at 15:00 America/New_York."
     )
 
     mock_get_deleted_template.assert_called_with(SERVICE_ONE_ID, template_id, None)
@@ -1591,7 +1591,7 @@ def test_should_show_page_for_a_deleted_template(
     )
     assert (
         page.select("p.hint")[0].text.strip()
-        == "This template was deleted today at 15:00 US/Eastern."
+        == "This template was deleted today at 15:00 America/New_York."
     )
     assert "Delete this template" not in page.select_one("main").text
 
diff --git a/tests/app/main/views/uploads/test_upload_hub.py b/tests/app/main/views/uploads/test_upload_hub.py
index ee24fba653..53ba1f161a 100644
--- a/tests/app/main/views/uploads/test_upload_hub.py
+++ b/tests/app/main/views/uploads/test_upload_hub.py
@@ -52,7 +52,7 @@ def test_get_upload_hub_page(
 
     assert normalize_spaces(uploads[0].text.strip()) == (
         "some.csv "
-        "Sent 1 January 2016 at 06:09 US/Eastern "
+        "Sent 1 January 2016 at 06:09 America/New_York "
         "0 pending 8 delivered 2 failed"
     )
     assert uploads[0].select_one("a.file-list-filename-large")["href"] == (
@@ -82,12 +82,12 @@ def test_uploads_page_shows_scheduled_jobs(
         ("File Status"),
         (
             "even_later.csv "
-            "Sending 1 January 2016 at 18:09 US/Eastern "
+            "Sending 1 January 2016 at 18:09 America/New_York "
             "1 text message waiting to send"
         ),
         (
             "send_me_later.csv "
-            "Sending 1 January 2016 at 06:09 US/Eastern "
+            "Sending 1 January 2016 at 06:09 America/New_York "
             "1 text message waiting to send"
         ),
     ]
diff --git a/tests/app/models/test_user.py b/tests/app/models/test_user.py
index 1caf85f4a5..099cab14d0 100644
--- a/tests/app/models/test_user.py
+++ b/tests/app/models/test_user.py
@@ -18,6 +18,7 @@ def test_user(notify_admin):
         "email_address": "test@user.gsa.gov",
         "mobile_number": "+12021231234",
         "state": "pending",
+        "preferred_timezone": "America/Chicago",
         "failed_login_count": 0,
         "platform_admin": False,
     }