diff --git a/esphome/__main__.py b/esphome/__main__.py
index 5f281ce832..dd97c6eee9 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -639,7 +639,7 @@ def run_miniterm(config: ConfigType, port: str, args) -> int:
                         chunk = ser.read(ser.in_waiting or 1)
                         if not chunk:
                             continue
-                        time_ = datetime.now()
+                        time_ = datetime.now().astimezone()
                         milliseconds = time_.microsecond // 1000
                         time_str = f"[{time_.hour:02}:{time_.minute:02}:{time_.second:02}.{milliseconds:03}]"
 
diff --git a/esphome/components/api/client.py b/esphome/components/api/client.py
index 327973a605..44edc035f9 100644
--- a/esphome/components/api/client.py
+++ b/esphome/components/api/client.py
@@ -119,7 +119,7 @@ async def async_run_logs(
 
     def on_log(msg: SubscribeLogsResponse) -> None:
         """Handle a new log message."""
-        time_ = datetime.now()
+        time_ = datetime.now().astimezone()
         message: bytes = msg.message
         text = message.decode("utf8", "backslashreplace")
         nanoseconds = time_.microsecond // 1000
diff --git a/esphome/components/zigbee/zigbee_zephyr.py b/esphome/components/zigbee/zigbee_zephyr.py
index aa16bbef53..39ecadfddf 100644
--- a/esphome/components/zigbee/zigbee_zephyr.py
+++ b/esphome/components/zigbee/zigbee_zephyr.py
@@ -161,7 +161,10 @@ async def _attr_to_code(config: ConfigType) -> None:
         zigbee_set_string(basic_attrs.mf_name, "esphome"),
         zigbee_set_string(basic_attrs.model_id, config[CONF_MODEL]),
         zigbee_set_string(
-            basic_attrs.date_code, datetime.datetime.now().strftime("%Y%m%d %H%M%S")
+            basic_attrs.date_code,
+            # Local build time, matching the esp32 implementation
+            # (App.get_build_time() in C++).
+            datetime.datetime.now().astimezone().strftime("%Y%m%d %H%M%S"),
         ),
         zigbee_assign(
             basic_attrs.power_source,
diff --git a/esphome/config_validation.py b/esphome/config_validation.py
index 1d5e27c9ae..f826b254ac 100644
--- a/esphome/config_validation.py
+++ b/esphome/config_validation.py
@@ -1183,7 +1183,9 @@ def date_time(date: bool, time: bool):
                 format += "%p"
 
         try:
-            date_obj = datetime.strptime(value, format)
+            # The generated format never includes %z/%Z, so this parses a
+            # naive wall-clock date/time by design.
+            date_obj = datetime.strptime(value, format)  # noqa: DTZ007
         except ValueError as err:
             raise Invalid(f"Invalid {exc_message}: {err}") from err
 
diff --git a/esphome/external_files.py b/esphome/external_files.py
index dfabc54f47..4e73c8dc21 100644
--- a/esphome/external_files.py
+++ b/esphome/external_files.py
@@ -7,6 +7,7 @@ from datetime import UTC, datetime
 import logging
 import os
 from pathlib import Path
+import time
 
 import requests
 
@@ -141,9 +142,11 @@ def has_remote_file_changed(
 
 def is_file_recent(file_path: Path, refresh: TimePeriodSeconds) -> bool:
     if file_path.exists():
-        creation_time = file_path.stat().st_ctime
-        current_time = datetime.now().timestamp()
-        return current_time - creation_time <= refresh.total_seconds
+        # st_mtime, not st_ctime: ctime is inode-change time on POSIX
+        # (bumped by chmod/chown/rename) so a metadata touch would make
+        # the file look fresh.
+        modification_time = file_path.stat().st_mtime
+        return time.time() - modification_time <= refresh.total_seconds
     return False
 
 
diff --git a/esphome/git.py b/esphome/git.py
index 094a6dae19..744ce35ef6 100644
--- a/esphome/git.py
+++ b/esphome/git.py
@@ -1,12 +1,12 @@
 from collections.abc import Callable
 from dataclasses import dataclass
-from datetime import datetime
 import hashlib
 import logging
 from pathlib import Path
 import re
 import subprocess
 import sys
+import time
 import urllib.parse
 
 import esphome.config_validation as cv
@@ -247,11 +247,11 @@ def clone_or_update(
             return repo_dir, None
 
         file_timestamp = Path(repo_dir / ".git" / "FETCH_HEAD")
-        # On first clone, FETCH_HEAD does not exists
+        # On first clone, FETCH_HEAD does not exist
         if not file_timestamp.exists():
             file_timestamp = Path(repo_dir / ".git" / "HEAD")
-        age = datetime.now() - datetime.fromtimestamp(file_timestamp.stat().st_mtime)
-        if refresh is None or age.total_seconds() > refresh.total_seconds:
+        age_seconds = time.time() - file_timestamp.stat().st_mtime
+        if refresh is None or age_seconds > refresh.total_seconds:
             # Try to update the repository, recovering from broken state if needed
             old_sha: str | None = None
             try:
diff --git a/esphome/mqtt.py b/esphome/mqtt.py
index d6bde0cbfd..c6a7a7558b 100644
--- a/esphome/mqtt.py
+++ b/esphome/mqtt.py
@@ -139,7 +139,7 @@ def show_discover(config, username=None, password=None, client_id=None):
     _LOGGER.info("Starting log output from %s", topic)
 
     def on_message(client, userdata, msg):
-        time_ = datetime.now().time().strftime("[%H:%M:%S]")
+        time_ = datetime.now().astimezone().time().strftime("[%H:%M:%S]")
         payload = msg.payload.decode(errors="backslashreplace")
         if len(payload) > 0:
             message = time_ + " " + payload
@@ -184,7 +184,7 @@ def get_esphome_device_ip(
 
     def on_message(client, userdata, msg):
         nonlocal dev_ip
-        time_ = datetime.now().time().strftime("[%H:%M:%S]")
+        time_ = datetime.now().astimezone().time().strftime("[%H:%M:%S]")
         payload = msg.payload.decode(errors="backslashreplace")
         if len(payload) > 0:
             message = time_ + " " + payload
@@ -253,7 +253,7 @@ def show_logs(config, topic=None, username=None, password=None, client_id=None):
     _LOGGER.info("Starting log output from %s", topic)
 
     def on_message(client, userdata, msg):
-        time_ = datetime.now().time().strftime("[%H:%M:%S]")
+        time_ = datetime.now().astimezone().time().strftime("[%H:%M:%S]")
         payload = msg.payload.decode(errors="backslashreplace")
         message = time_ + payload
         safe_print(message)
diff --git a/esphome/storage_json.py b/esphome/storage_json.py
index 7f8885ba5f..04f5881465 100644
--- a/esphome/storage_json.py
+++ b/esphome/storage_json.py
@@ -338,7 +338,10 @@ class EsphomeStorageJSON:
     @property
     def last_update_check(self) -> datetime | None:
         try:
-            return datetime.strptime(self.last_update_check_str, "%Y-%m-%dT%H:%M:%S")
+            # Stored format is naive ISO without %z; preserved for backward compat.
+            return datetime.strptime(  # noqa: DTZ007
+                self.last_update_check_str, "%Y-%m-%dT%H:%M:%S"
+            )
         except Exception:  # pylint: disable=broad-except
             return None
 
diff --git a/pyproject.toml b/pyproject.toml
index 6572078746..d92c7ba894 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -113,6 +113,7 @@ exclude = ['generated']
 select = [
   "B",    # flake8-bugbear
   "C4",   # flake8-comprehensions
+  "DTZ",  # flake8-datetimez
   "E",    # pycodestyle
   "EXE",  # flake8-executable
   "F",    # pyflakes/autoflake
diff --git a/tests/unit_tests/test_external_files.py b/tests/unit_tests/test_external_files.py
index 64ef149581..16cee9564f 100644
--- a/tests/unit_tests/test_external_files.py
+++ b/tests/unit_tests/test_external_files.py
@@ -120,7 +120,7 @@ def test_is_file_recent_with_old_file(setup_core: Path) -> None:
 
     old_time = time.time() - 7200
     mock_stat = MagicMock()
-    mock_stat.st_ctime = old_time
+    mock_stat.st_mtime = old_time
 
     with patch.object(Path, "stat", return_value=mock_stat):
         refresh = TimePeriod(seconds=3600)
@@ -147,7 +147,7 @@ def test_is_file_recent_with_zero_refresh(setup_core: Path) -> None:
 
     # Mock stat to return a time 10 seconds ago
     mock_stat = MagicMock()
-    mock_stat.st_ctime = time.time() - 10
+    mock_stat.st_mtime = time.time() - 10
     with patch.object(Path, "stat", return_value=mock_stat):
         refresh = TimePeriod(seconds=0)
         result = external_files.is_file_recent(test_file, refresh)
diff --git a/tests/unit_tests/test_git.py b/tests/unit_tests/test_git.py
index 690c47c183..62d2344069 100644
--- a/tests/unit_tests/test_git.py
+++ b/tests/unit_tests/test_git.py
@@ -1,8 +1,8 @@
 """Tests for git.py module."""
 
-from datetime import datetime, timedelta
 import os
 from pathlib import Path
+import time
 from typing import Any
 from unittest.mock import Mock, patch
 
@@ -34,9 +34,9 @@ def _setup_old_repo(repo_dir: Path, days_old: int = 2) -> None:
     # Create FETCH_HEAD file with old timestamp
     fetch_head = git_dir / "FETCH_HEAD"
     fetch_head.write_text("test")
-    old_time = datetime.now() - timedelta(days=days_old)
+    old_time = time.time() - days_old * 86400
     fetch_head.touch()
-    os.utime(fetch_head, (old_time.timestamp(), old_time.timestamp()))
+    os.utime(fetch_head, (old_time, old_time))
 
 
 def _get_git_command_type(cmd: list[str]) -> str | None:
@@ -285,10 +285,10 @@ def test_clone_or_update_with_refresh_updates_old_repo(
     # Create FETCH_HEAD file with old timestamp (2 days ago)
     fetch_head = git_dir / "FETCH_HEAD"
     fetch_head.write_text("test")
-    old_time = datetime.now() - timedelta(days=2)
+    old_time = time.time() - 2 * 86400
     fetch_head.touch()  # Create the file
     # Set modification time to 2 days ago
-    os.utime(fetch_head, (old_time.timestamp(), old_time.timestamp()))
+    os.utime(fetch_head, (old_time, old_time))
 
     # Mock git command responses
     mock_run_git_command.return_value = "abc123"  # SHA for rev-parse
@@ -333,10 +333,10 @@ def test_clone_or_update_with_refresh_skips_fresh_repo(
     # Create FETCH_HEAD file with recent timestamp (1 hour ago)
     fetch_head = git_dir / "FETCH_HEAD"
     fetch_head.write_text("test")
-    recent_time = datetime.now() - timedelta(hours=1)
+    recent_time = time.time() - 3600
     fetch_head.touch()  # Create the file
     # Set modification time to 1 hour ago
-    os.utime(fetch_head, (recent_time.timestamp(), recent_time.timestamp()))
+    os.utime(fetch_head, (recent_time, recent_time))
 
     # Call with refresh=1d (1 day)
     refresh = TimePeriodSeconds(days=1)
@@ -409,10 +409,10 @@ def test_clone_or_update_with_none_refresh_always_updates(
     # Create FETCH_HEAD file with very recent timestamp (1 second ago)
     fetch_head = git_dir / "FETCH_HEAD"
     fetch_head.write_text("test")
-    recent_time = datetime.now() - timedelta(seconds=1)
+    recent_time = time.time() - 1
     fetch_head.touch()  # Create the file
     # Set modification time to 1 second ago
-    os.utime(fetch_head, (recent_time.timestamp(), recent_time.timestamp()))
+    os.utime(fetch_head, (recent_time, recent_time))
 
     # Mock git command responses
     mock_run_git_command.return_value = "abc123"  # SHA for rev-parse
diff --git a/tests/unit_tests/test_storage_json.py b/tests/unit_tests/test_storage_json.py
index ea37492cf4..b3f8a05605 100644
--- a/tests/unit_tests/test_storage_json.py
+++ b/tests/unit_tests/test_storage_json.py
@@ -576,8 +576,8 @@ def test_esphome_storage_json_last_update_check_property() -> None:
     assert result.hour == 10
     assert result.minute == 30
 
-    # Test setter
-    new_date = datetime(2024, 2, 20, 15, 45, 30)
+    # Test setter — naive datetime matches the storage round-trip format.
+    new_date = datetime(2024, 2, 20, 15, 45, 30)  # noqa: DTZ001
     storage.last_update_check = new_date
     assert storage.last_update_check_str == "2024-02-20T15:45:30"