From 876ab37064d50252e6a55a69c709b819acc1cdb5 Mon Sep 17 00:00:00 2001
From: RussellAult <RussellAult@users.noreply.github.com>
Date: Mon, 31 Aug 2026 09:21:56 -0600
Subject: [PATCH] Add kPa as a valid unit of measurement for pressure in
 weather entity (#165519)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 homeassistant/components/weather/const.py        |  1 +
 .../components/weather/significant_change.py     |  2 ++
 .../weather/test_significant_change.py           | 16 ++++++++++++++++
 tests/components/weather/test_websocket_api.py   |  2 +-
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/weather/const.py b/homeassistant/components/weather/const.py
index f45c04145620..3e56f5e118de 100644
--- a/homeassistant/components/weather/const.py
+++ b/homeassistant/components/weather/const.py
@@ -81,6 +81,7 @@ INTENT_GET_WEATHER = "HassGetWeather"
 
 VALID_UNITS_PRESSURE: set[str] = {
     UnitOfPressure.HPA,
+    UnitOfPressure.KPA,
     UnitOfPressure.MBAR,
     UnitOfPressure.INHG,
     UnitOfPressure.MMHG,
diff --git a/homeassistant/components/weather/significant_change.py b/homeassistant/components/weather/significant_change.py
index 70d837b1dd2d..7deb5de2beb6 100644
--- a/homeassistant/components/weather/significant_change.py
+++ b/homeassistant/components/weather/significant_change.py
@@ -145,6 +145,8 @@ def async_check_significant_change(
                 UnitOfPressure.MMHG,  # 1hPa = 0.75mmHg
             ):
                 absolute_change = 1.0
+            elif unit == UnitOfPressure.KPA:  # 1hPa = 0.1 kPa
+                absolute_change = 0.1
             elif unit == UnitOfPressure.INHG:  # 1hPa = 0.03inHg
                 absolute_change = 0.05
 
diff --git a/tests/components/weather/test_significant_change.py b/tests/components/weather/test_significant_change.py
index 93e5830a0acb..3230fa3c35b0 100644
--- a/tests/components/weather/test_significant_change.py
+++ b/tests/components/weather/test_significant_change.py
@@ -168,6 +168,14 @@ async def test_significant_state_change() -> None:
             },
             False,
         ),
+        (
+            {ATTR_WEATHER_PRESSURE: 100},
+            {
+                ATTR_WEATHER_PRESSURE: 100.09,
+                ATTR_WEATHER_PRESSURE_UNIT: UnitOfPressure.KPA,
+            },
+            False,
+        ),
         (
             {ATTR_WEATHER_PRESSURE: 29.5},
             {
@@ -280,6 +288,14 @@ async def test_significant_state_change() -> None:
             },
             True,
         ),
+        (
+            {ATTR_WEATHER_PRESSURE: 100},
+            {
+                ATTR_WEATHER_PRESSURE: 100.11,
+                ATTR_WEATHER_PRESSURE_UNIT: UnitOfPressure.KPA,
+            },
+            True,
+        ),
         (
             {ATTR_WEATHER_PRESSURE: 29.5},
             {
diff --git a/tests/components/weather/test_websocket_api.py b/tests/components/weather/test_websocket_api.py
index 11c5baafa301..0cb1ae3c1580 100644
--- a/tests/components/weather/test_websocket_api.py
+++ b/tests/components/weather/test_websocket_api.py
@@ -30,7 +30,7 @@ async def test_device_class_units(
     assert msg["result"] == {
         "units": {
             "precipitation_unit": ["in", "mm"],
-            "pressure_unit": ["hPa", "inHg", "mbar", "mmHg"],
+            "pressure_unit": ["hPa", "inHg", "kPa", "mbar", "mmHg"],
             "temperature_unit": ["°C", "°F"],
             "visibility_unit": ["km", "mi"],
             "wind_speed_unit": ["Beaufort", "ft/s", "km/h", "kn", "m/s", "mph"],