diff --git a/homeassistant/components/recorder/models.py b/homeassistant/components/recorder/models.py
index 9faedbbdb1e..2f71324fac0 100644
--- a/homeassistant/components/recorder/models.py
+++ b/homeassistant/components/recorder/models.py
@@ -55,10 +55,6 @@ SCHEMA_VERSION = 28
 
 _LOGGER = logging.getLogger(__name__)
 
-# EPOCHORDINAL is not exposed as a constant
-# https://github.com/python/cpython/blob/3.10/Lib/zoneinfo/_zoneinfo.py#L12
-EPOCHORDINAL = datetime(1970, 1, 1).toordinal()
-
 DB_TIMEZONE = "+00:00"
 
 TABLE_EVENTS = "events"
@@ -649,16 +645,8 @@ def process_datetime_to_timestamp(ts: datetime) -> float:
     Mirrors the behavior of process_timestamp_to_utc_isoformat
     except it returns the epoch time.
     """
-    if ts.tzinfo is None:
-        # Taken from
-        # https://github.com/python/cpython/blob/3.10/Lib/zoneinfo/_zoneinfo.py#L185
-        return (
-            (ts.toordinal() - EPOCHORDINAL) * 86400
-            + ts.hour * 3600
-            + ts.minute * 60
-            + ts.second
-            + (ts.microsecond / 1000000)
-        )
+    if ts.tzinfo is None or ts.tzinfo == dt_util.UTC:
+        return dt_util.utc_to_timestamp(ts)
     return ts.timestamp()
 
 
diff --git a/homeassistant/core.py b/homeassistant/core.py
index 916dd0c6f72..061695ade6a 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -734,7 +734,9 @@ class Event:
         self.data = data or {}
         self.origin = origin
         self.time_fired = time_fired or dt_util.utcnow()
-        self.context: Context = context or Context()
+        self.context: Context = context or Context(
+            id=ulid_util.ulid(dt_util.utc_to_timestamp(self.time_fired))
+        )
 
     def __hash__(self) -> int:
         """Make hashable."""
@@ -1363,11 +1365,11 @@ class StateMachine:
         if same_state and same_attr:
             return
 
-        if context is None:
-            context = Context()
-
         now = dt_util.utcnow()
 
+        if context is None:
+            context = Context(id=ulid_util.ulid(dt_util.utc_to_timestamp(now)))
+
         state = State(
             entity_id,
             new_state,
diff --git a/homeassistant/util/dt.py b/homeassistant/util/dt.py
index 4b4b798a2d8..7c0a4923e71 100644
--- a/homeassistant/util/dt.py
+++ b/homeassistant/util/dt.py
@@ -14,6 +14,10 @@ DATE_STR_FORMAT = "%Y-%m-%d"
 UTC = dt.timezone.utc
 DEFAULT_TIME_ZONE: dt.tzinfo = dt.timezone.utc
 
+# EPOCHORDINAL is not exposed as a constant
+# https://github.com/python/cpython/blob/3.10/Lib/zoneinfo/_zoneinfo.py#L12
+EPOCHORDINAL = dt.datetime(1970, 1, 1).toordinal()
+
 # Copyright (c) Django Software Foundation and individual contributors.
 # All rights reserved.
 # https://github.com/django/django/blob/master/LICENSE
@@ -98,6 +102,19 @@ def utc_from_timestamp(timestamp: float) -> dt.datetime:
     return dt.datetime.utcfromtimestamp(timestamp).replace(tzinfo=UTC)
 
 
+def utc_to_timestamp(utc_dt: dt.datetime) -> float:
+    """Fast conversion of a datetime in UTC to a timestamp."""
+    # Taken from
+    # https://github.com/python/cpython/blob/3.10/Lib/zoneinfo/_zoneinfo.py#L185
+    return (
+        (utc_dt.toordinal() - EPOCHORDINAL) * 86400
+        + utc_dt.hour * 3600
+        + utc_dt.minute * 60
+        + utc_dt.second
+        + (utc_dt.microsecond / 1000000)
+    )
+
+
 def start_of_local_day(dt_or_d: dt.date | dt.datetime | None = None) -> dt.datetime:
     """Return local datetime object of start of day from date or datetime."""
     if dt_or_d is None:
diff --git a/homeassistant/util/ulid.py b/homeassistant/util/ulid.py
index c38d95bd169..d40b0f48e16 100644
--- a/homeassistant/util/ulid.py
+++ b/homeassistant/util/ulid.py
@@ -1,4 +1,5 @@
 """Helpers to generate ulids."""
+from __future__ import annotations
 
 from random import getrandbits
 import time
@@ -17,7 +18,7 @@ def ulid_hex() -> str:
     return f"{int(time.time()*1000):012x}{getrandbits(80):020x}"
 
 
-def ulid() -> str:
+def ulid(timestamp: float | None = None) -> str:
     """Generate a ULID.
 
     This ulid should not be used for cryptographically secure
@@ -34,9 +35,9 @@ def ulid() -> str:
     import ulid
     ulid.parse(ulid_util.ulid())
     """
-    ulid_bytes = int(time.time() * 1000).to_bytes(6, byteorder="big") + int(
-        getrandbits(80)
-    ).to_bytes(10, byteorder="big")
+    ulid_bytes = int((timestamp or time.time()) * 1000).to_bytes(
+        6, byteorder="big"
+    ) + int(getrandbits(80)).to_bytes(10, byteorder="big")
 
     # This is base32 crockford encoding with the loop unrolled for performance
     #
diff --git a/tests/components/generic_hygrostat/test_humidifier.py b/tests/components/generic_hygrostat/test_humidifier.py
index d0412731c78..b27b6324f86 100644
--- a/tests/components/generic_hygrostat/test_humidifier.py
+++ b/tests/components/generic_hygrostat/test_humidifier.py
@@ -811,7 +811,7 @@ async def test_humidity_change_dry_trigger_on_not_long_enough(hass, setup_comp_4
 async def test_humidity_change_dry_trigger_on_long_enough(hass, setup_comp_4):
     """Test if humidity change turn dry on."""
     fake_changed = datetime.datetime(
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
+        1970, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
     )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
@@ -845,7 +845,7 @@ async def test_humidity_change_dry_trigger_off_not_long_enough(hass, setup_comp_
 async def test_humidity_change_dry_trigger_off_long_enough(hass, setup_comp_4):
     """Test if humidity change turn dry on."""
     fake_changed = datetime.datetime(
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
+        1970, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
     )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
@@ -967,7 +967,7 @@ async def test_humidity_change_humidifier_trigger_on_not_long_enough(
 async def test_humidity_change_humidifier_trigger_on_long_enough(hass, setup_comp_6):
     """Test if humidity change turn humidifier on after min cycle."""
     fake_changed = datetime.datetime(
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
+        1970, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
     )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
@@ -989,7 +989,7 @@ async def test_humidity_change_humidifier_trigger_on_long_enough(hass, setup_com
 async def test_humidity_change_humidifier_trigger_off_long_enough(hass, setup_comp_6):
     """Test if humidity change turn humidifier off after min cycle."""
     fake_changed = datetime.datetime(
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
+        1970, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
     )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
diff --git a/tests/components/generic_thermostat/test_climate.py b/tests/components/generic_thermostat/test_climate.py
index d607c6dbb61..c4d23b41579 100644
--- a/tests/components/generic_thermostat/test_climate.py
+++ b/tests/components/generic_thermostat/test_climate.py
@@ -749,7 +749,7 @@ async def test_temp_change_ac_trigger_on_not_long_enough(hass, setup_comp_4):
 
 async def test_temp_change_ac_trigger_on_long_enough(hass, setup_comp_4):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -775,7 +775,7 @@ async def test_temp_change_ac_trigger_off_not_long_enough(hass, setup_comp_4):
 
 async def test_temp_change_ac_trigger_off_long_enough(hass, setup_comp_4):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -855,7 +855,7 @@ async def test_temp_change_ac_trigger_on_not_long_enough_2(hass, setup_comp_5):
 
 async def test_temp_change_ac_trigger_on_long_enough_2(hass, setup_comp_5):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -881,7 +881,7 @@ async def test_temp_change_ac_trigger_off_not_long_enough_2(hass, setup_comp_5):
 
 async def test_temp_change_ac_trigger_off_long_enough_2(hass, setup_comp_5):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -969,7 +969,7 @@ async def test_temp_change_heater_trigger_on_not_long_enough(hass, setup_comp_6)
 
 async def test_temp_change_heater_trigger_on_long_enough(hass, setup_comp_6):
     """Test if temperature change turn heater on after min cycle."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -986,7 +986,7 @@ async def test_temp_change_heater_trigger_on_long_enough(hass, setup_comp_6):
 
 async def test_temp_change_heater_trigger_off_long_enough(hass, setup_comp_6):
     """Test if temperature change turn heater off after min cycle."""
-    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
+    fake_changed = datetime.datetime(1970, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
diff --git a/tests/test_core.py b/tests/test_core.py
index c870605fc01..104828f64e1 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1,5 +1,8 @@
 """Test to verify that Home Assistant core works."""
+from __future__ import annotations
+
 # pylint: disable=protected-access
+import array
 import asyncio
 from datetime import datetime, timedelta
 import functools
@@ -28,6 +31,7 @@ from homeassistant.const import (
     __version__,
 )
 import homeassistant.core as ha
+from homeassistant.core import State
 from homeassistant.exceptions import (
     InvalidEntityFormatError,
     InvalidStateError,
@@ -1489,9 +1493,300 @@ async def test_reserving_states(hass):
     assert hass.states.async_available("light.bedroom") is True
 
 
-async def test_state_change_events_match_state_time(hass):
-    """Test last_updated and timed_fired only call utcnow once."""
+def _ulid_timestamp(ulid: str) -> int:
+    encoded = ulid[:10].encode("ascii")
+    # This unpacks the time from the ulid
 
+    # Copied from
+    # https://github.com/ahawker/ulid/blob/06289583e9de4286b4d80b4ad000d137816502ca/ulid/base32.py#L296
+    decoding = array.array(
+        "B",
+        (
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0x00,
+            0x01,
+            0x02,
+            0x03,
+            0x04,
+            0x05,
+            0x06,
+            0x07,
+            0x08,
+            0x09,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0x0A,
+            0x0B,
+            0x0C,
+            0x0D,
+            0x0E,
+            0x0F,
+            0x10,
+            0x11,
+            0x01,
+            0x12,
+            0x13,
+            0x01,
+            0x14,
+            0x15,
+            0x00,
+            0x16,
+            0x17,
+            0x18,
+            0x19,
+            0x1A,
+            0xFF,
+            0x1B,
+            0x1C,
+            0x1D,
+            0x1E,
+            0x1F,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0x0A,
+            0x0B,
+            0x0C,
+            0x0D,
+            0x0E,
+            0x0F,
+            0x10,
+            0x11,
+            0x01,
+            0x12,
+            0x13,
+            0x01,
+            0x14,
+            0x15,
+            0x00,
+            0x16,
+            0x17,
+            0x18,
+            0x19,
+            0x1A,
+            0xFF,
+            0x1B,
+            0x1C,
+            0x1D,
+            0x1E,
+            0x1F,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+            0xFF,
+        ),
+    )
+    return int.from_bytes(
+        bytes(
+            (
+                ((decoding[encoded[0]] << 5) | decoding[encoded[1]]) & 0xFF,
+                ((decoding[encoded[2]] << 3) | (decoding[encoded[3]] >> 2)) & 0xFF,
+                (
+                    (decoding[encoded[3]] << 6)
+                    | (decoding[encoded[4]] << 1)
+                    | (decoding[encoded[5]] >> 4)
+                )
+                & 0xFF,
+                ((decoding[encoded[5]] << 4) | (decoding[encoded[6]] >> 1)) & 0xFF,
+                (
+                    (decoding[encoded[6]] << 7)
+                    | (decoding[encoded[7]] << 2)
+                    | (decoding[encoded[8]] >> 3)
+                )
+                & 0xFF,
+                ((decoding[encoded[8]] << 5) | (decoding[encoded[9]])) & 0xFF,
+            )
+        ),
+        byteorder="big",
+    )
+
+
+async def test_state_change_events_context_id_match_state_time(hass):
+    """Test last_updated, timed_fired, and the ulid all have the same time."""
     events = []
 
     @ha.callback
@@ -1502,6 +1797,31 @@ async def test_state_change_events_match_state_time(hass):
 
     hass.states.async_set("light.bedroom", "on")
     await hass.async_block_till_done()
-    state = hass.states.get("light.bedroom")
-
+    state: State = hass.states.get("light.bedroom")
     assert state.last_updated == events[0].time_fired
+    assert len(state.context.id) == 26
+    # ULIDs store time to 3 decimal places compared to python timestamps
+    assert _ulid_timestamp(state.context.id) == int(
+        state.last_updated.timestamp() * 1000
+    )
+
+
+async def test_state_firing_event_matches_context_id_ulid_time(hass):
+    """Test timed_fired and the ulid have the same time."""
+    events = []
+
+    @ha.callback
+    def _event_listener(event):
+        events.append(event)
+
+    hass.bus.async_listen(EVENT_HOMEASSISTANT_STARTED, _event_listener)
+
+    hass.bus.async_fire(EVENT_HOMEASSISTANT_STARTED)
+    await hass.async_block_till_done()
+
+    event = events[0]
+    assert len(event.context.id) == 26
+    # ULIDs store time to 3 decimal places compared to python timestamps
+    assert _ulid_timestamp(event.context.id) == int(
+        events[0].time_fired.timestamp() * 1000
+    )
diff --git a/tests/util/test_dt.py b/tests/util/test_dt.py
index d2c453f070d..6e499e6e6f1 100644
--- a/tests/util/test_dt.py
+++ b/tests/util/test_dt.py
@@ -106,6 +106,12 @@ def test_utc_from_timestamp():
     )
 
 
+def test_timestamp_to_utc():
+    """Test we can convert a utc datetime to a timestamp."""
+    utc_now = dt_util.utcnow()
+    assert dt_util.utc_to_timestamp(utc_now) == utc_now.timestamp()
+
+
 def test_as_timestamp():
     """Test as_timestamp method."""
     ts = 1462401234