Temperature-based light color
Automatically change the color of one or more Home Assistant lights based on a temperature sensor.
Features
Use a temperature sensor to control one or more lights
RGB color interpolation between configurable cold, normal, and hot colors
Color-temperature interpolation between configurable Kelvin values- Configurable minimum, normal, and maximum temperatures
Configurable light transition duration
Optional minimum temperature-change threshold to reduce unnecessary updates- Option to update only lights that are already on
Automatically synchronizes a light when it is turned on
Synchronizes eligible lights when Home Assistant starts
Ignores unavailable and unknown temperature sensor states
Temperatures outside the configured range use the corresponding endpoint color
The temperature range is divided into two phases:
Cold ─────────────► Normal ─────────────► Hot
The configured normal color is reached at the configured normal temperature.
Requirements
Temperature sensor
The selected sensor must:
- Be a
sensorentity - Have the
temperaturedevice class - Provide a numeric temperature state
- Use °C, as the blueprint’s temperature thresholds are configured in °C
Lights
One or more light entities can be selected.
For RGB mode, the lights must support RGB color.
For Color temperature mode, the lights must support color temperature and a compatible Kelvin range.
The exact result can depend on the capabilities of the individual light or light integration.
Only update lights that are already on
This option is enabled by default.
When enabled, temperature changes only affect lights that are currently on. The blueprint will not turn an off light on.
When a configured light is subsequently turned on, its color is automatically synchronized with the current temperature.
If the option is disabled, the blueprint can also update lights that are currently off, which may turn them on.
Minimum temperature change
Use Minimum temperature change to prevent frequent small sensor fluctuations from causing unnecessary light updates.
For example, with a threshold of 0.5 °C, changes smaller than 0.5 °C are ignored.
Set it to 0 to process every temperature state change.
Temperature range
The configured temperatures must satisfy:
Minimum < Normal < Maximum
Temperatures below or above the configured range are clamped to the cold or hot color respectively.
For more detailed information about the interpolation, configuration options, and troubleshooting, see the project README.
Installation
Click the Import Blueprint button at the top of this post, or import the blueprint manually using:
Alternatively:
- Go to Settings → Automations & scenes → Blueprints
- Select Import Blueprint
- Enter the raw GitHub URL
- Select Preview
- Import the blueprint
Full blueprint
blueprint:
name: Temperature-based light color
description: >
Changes the color of one or more lights based on a configurable
temperature sensor.
The color changes through three configurable temperature points:
cold, normal, and hot.
The transition is split into two phases:
cold → normal and normal → hot.
For RGB mode, the colors are interpolated between the three
configured RGB colors. This allows colors such as blue → green →
red, with the intermediate transition naturally passing through
cyan, yellow, orange, and other intermediate colors.
For color-temperature mode, the Kelvin value is interpolated
through the same three temperature points.
When "Only update lights that are already on" is enabled, the
automation never turns an off light on. When a light is subsequently
turned on, its color is synchronized with the current temperature.
The configured color is also applied to eligible lights when
Home Assistant starts.
domain: automation
author: tobus3000
source_url: https://github.com/tobus3000/hass-temperature-based-light-color-blueprint
homeassistant:
min_version: "2024.10.0"
input:
temperature_sensor:
name: Temperature sensor
description: >
The temperature sensor whose value controls the light color.
The sensor state must be expressed in °C.
selector:
entity:
filter:
- domain: sensor
device_class: temperature
target_lights:
name: Lights
description: >
One or more lights whose color should follow the temperature.
The selected lights must support the selected color mode.
selector:
entity:
multiple: true
filter:
- domain: light
color_mode:
name: Color mode
description: >
Choose between RGB color interpolation and color-temperature
interpolation.
default: rgb
selector:
select:
options:
- label: RGB color
value: rgb
- label: Color temperature
value: color_temperature
min_temperature:
name: Minimum temperature
description: >
At or below this temperature, the cold color is used.
Temperature thresholds are expressed in °C.
Must be lower than the normal and maximum temperatures.
default: 0
selector:
number:
min: -50
max: 100
step: 0.5
unit_of_measurement: "°C"
mode: box
normal_temperature:
name: Normal temperature
description: >
The temperature at which the normal color is used.
Temperature thresholds are expressed in °C.
Must be between the minimum and maximum temperatures.
default: 20
selector:
number:
min: -50
max: 100
step: 0.5
unit_of_measurement: "°C"
mode: box
max_temperature:
name: Maximum temperature
description: >
At or above this temperature, the hot color is used.
Temperature thresholds are expressed in °C.
Must be higher than the normal and minimum temperatures.
default: 30
selector:
number:
min: -50
max: 100
step: 0.5
unit_of_measurement: "°C"
mode: box
cold_temperature_rgb:
name: Cold color
description: >
RGB color used at or below the minimum temperature.
default: [0, 100, 255]
selector:
color_rgb:
normal_temperature_rgb:
name: Normal color
description: >
RGB color used at the normal temperature.
default: [0, 255, 0]
selector:
color_rgb:
hot_temperature_rgb:
name: Hot color
description: >
RGB color used at or above the maximum temperature.
default: [255, 0, 0]
selector:
color_rgb:
cold_temperature_kelvin:
name: Cold color temperature
description: >
Kelvin value used at or below the minimum temperature.
default: 6500
selector:
color_temp:
unit: kelvin
min: 2000
max: 6500
normal_temperature_kelvin:
name: Normal color temperature
description: >
Kelvin value used at the normal temperature.
default: 4000
selector:
color_temp:
unit: kelvin
min: 2000
max: 6500
hot_temperature_kelvin:
name: Hot color temperature
description: >
Kelvin value used at or above the maximum temperature.
default: 2700
selector:
color_temp:
unit: kelvin
min: 2000
max: 6500
transition:
name: Transition
description: >
Duration of the color transition.
default: 2
selector:
number:
min: 0
max: 60
step: 0.5
unit_of_measurement: seconds
mode: box
min_temperature_change:
name: Minimum temperature change
description: >
Ignore temperature changes smaller than this amount.
Set to 0 to react to every sensor state change.
default: 0.5
selector:
number:
min: 0
max: 10
step: 0.1
unit_of_measurement: "°C"
mode: box
only_update_lights_that_are_on:
name: Only update lights that are already on
description: >
When enabled, off lights are never turned on by this automation.
When a light is subsequently turned on, its color is synchronized
with the current temperature.
default: true
selector:
boolean:
mode: restart
variables:
temperature_sensor: !input temperature_sensor
target_lights: !input target_lights
color_mode: !input color_mode
min_temperature: !input min_temperature
normal_temperature: !input normal_temperature
max_temperature: !input max_temperature
cold_temperature_rgb: !input cold_temperature_rgb
normal_temperature_rgb: !input normal_temperature_rgb
hot_temperature_rgb: !input hot_temperature_rgb
cold_temperature_kelvin: !input cold_temperature_kelvin
normal_temperature_kelvin: !input normal_temperature_kelvin
hot_temperature_kelvin: !input hot_temperature_kelvin
transition: !input transition
min_temperature_change: !input min_temperature_change
only_update_lights_that_are_on: !input only_update_lights_that_are_on
temperature: "{{ states(temperature_sensor) | float(0) }}"
trigger:
- trigger: state
entity_id: !input temperature_sensor
to: null
id: temperature_changed
- trigger: state
entity_id: !input target_lights
to: "on"
id: light_turned_on
- trigger: homeassistant
event: start
id: home_assistant_started
condition:
- condition: template
value_template: >
{{ is_number(states(temperature_sensor)) }}
- condition: template
value_template: >
{{
min_temperature < normal_temperature
and normal_temperature < max_temperature
}}
- condition: template
value_template: >
{% if trigger.id != 'temperature_changed' %}
true
{% elif trigger.from_state is none %}
true
{% elif trigger.from_state.state in ['unknown', 'unavailable', 'none', ''] %}
true
{% else %}
{{
(
states(temperature_sensor) | float(0)
- trigger.from_state.state | float(0)
) | abs >= min_temperature_change
}}
{% endif %}
action:
- variables:
lights_to_update: >
{% if trigger.id == 'light_turned_on' %}
{{ [trigger.entity_id] }}
{% elif only_update_lights_that_are_on %}
{{
expand(target_lights)
| selectattr('state', 'eq', 'on')
| map(attribute='entity_id')
| list
}}
{% else %}
{{ target_lights }}
{% endif %}
- condition: template
value_template: >
{{ lights_to_update | count > 0 }}
- choose:
- conditions:
- condition: template
value_template: "{{ color_mode == 'rgb' }}"
sequence:
- variables:
red: >
{% set t = temperature | float(0) %}
{% if t <= min_temperature %}
{{ cold_temperature_rgb[0] | int }}
{% elif t < normal_temperature %}
{{
(
cold_temperature_rgb[0]
+ (
(
(t - min_temperature)
/ (normal_temperature - min_temperature)
)
* (
normal_temperature_rgb[0]
- cold_temperature_rgb[0]
)
)
) | round(0) | int
}}
{% elif t < max_temperature %}
{{
(
normal_temperature_rgb[0]
+ (
(
(t - normal_temperature)
/ (max_temperature - normal_temperature)
)
* (
hot_temperature_rgb[0]
- normal_temperature_rgb[0]
)
)
) | round(0) | int
}}
{% else %}
{{ hot_temperature_rgb[0] | int }}
{% endif %}
green: >
{% set t = temperature | float(0) %}
{% if t <= min_temperature %}
{{ cold_temperature_rgb[1] | int }}
{% elif t < normal_temperature %}
{{
(
cold_temperature_rgb[1]
+ (
(
(t - min_temperature)
/ (normal_temperature - min_temperature)
)
* (
normal_temperature_rgb[1]
- cold_temperature_rgb[1]
)
)
) | round(0) | int
}}
{% elif t < max_temperature %}
{{
(
normal_temperature_rgb[1]
+ (
(
(t - normal_temperature)
/ (max_temperature - normal_temperature)
)
* (
hot_temperature_rgb[1]
- normal_temperature_rgb[1]
)
)
) | round(0) | int
}}
{% else %}
{{ hot_temperature_rgb[1] | int }}
{% endif %}
blue: >
{% set t = temperature | float(0) %}
{% if t <= min_temperature %}
{{ cold_temperature_rgb[2] | int }}
{% elif t < normal_temperature %}
{{
(
cold_temperature_rgb[2]
+ (
(
(t - min_temperature)
/ (normal_temperature - min_temperature)
)
* (
normal_temperature_rgb[2]
- cold_temperature_rgb[2]
)
)
) | round(0) | int
}}
{% elif t < max_temperature %}
{{
(
normal_temperature_rgb[2]
+ (
(
(t - normal_temperature)
/ (max_temperature - normal_temperature)
)
* (
hot_temperature_rgb[2]
- normal_temperature_rgb[2]
)
)
) | round(0) | int
}}
{% else %}
{{ hot_temperature_rgb[2] | int }}
{% endif %}
- action: light.turn_on
target:
entity_id: "{{ lights_to_update }}"
data:
rgb_color:
- "{{ red }}"
- "{{ green }}"
- "{{ blue }}"
transition: "{{ transition }}"
- conditions:
- condition: template
value_template: "{{ color_mode == 'color_temperature' }}"
sequence:
- variables:
color_temperature_kelvin: >
{% set t = temperature | float(0) %}
{% if t <= min_temperature %}
{{ cold_temperature_kelvin | int }}
{% elif t < normal_temperature %}
{{
(
cold_temperature_kelvin
+ (
(
(t - min_temperature)
/ (normal_temperature - min_temperature)
)
* (
normal_temperature_kelvin
- cold_temperature_kelvin
)
)
) | round(0) | int
}}
{% elif t < max_temperature %}
{{
(
normal_temperature_kelvin
+ (
(
(t - normal_temperature)
/ (max_temperature - normal_temperature)
)
* (
hot_temperature_kelvin
- normal_temperature_kelvin
)
)
) | round(0) | int
}}
{% else %}
{{ hot_temperature_kelvin | int }}
{% endif %}
- action: light.turn_on
target:
entity_id: "{{ lights_to_update }}"
data:
color_temp_kelvin: "{{ color_temperature_kelvin }}"
transition: "{{ transition }}"
Source
Repository and issue tracking:
https://github.com/tobus3000/hass-temperature-based-light-color-blueprint