Home Assistant 2026.3 Broke Smart Light Color Temperature — Mired to Kelvin Migration
- Home Assistant 2026.3 removed deprecated mired-based color temperature attributes
- ATTR_KELVIN and ATTR_COLOR_TEMP removed from light.turn_on service
- Integrations using the old mired API no longer pass color temperature values
Problem Description
After updating to Home Assistant 2026.3, your smart lights no longer respond to color temperature changes. You can turn lights on and off, and brightness works, but setting warm white or cool white through the color temperature slider does nothing. The lights either stay at their default color temperature or the slider has no effect. This affects LocalTuya lights, some custom integrations, and any integration that still used the deprecated mired-based color temperature attributes.
Why This Happens in Real Homes
This was a long time coming but it still caught people off guard. Home Assistant deprecated mired-based color temperature back in December 2024 and gave integrations over a year to migrate. In 2026.3 they finally pulled the plug and removed ATTR_COLOR_TEMP and ATTR_KELVIN from the light.turn_on service. Everything has to use ATTR_COLOR_TEMP_KELVIN now. The official integrations were ready but a lot of popular HACS integrations were not — LocalTuya being the biggest one. Your lights turn on, brightness works, but the color temperature slider does absolutely nothing. The LocalTuya maintainers pushed a fix within days but if you are running any other custom light integrations, check their GitHub repos for kelvin migration PRs.
Symptoms
- Color temperature slider has no effect on smart lights after HA 2026.3 update
- Lights turn on and brightness works but color temperature is ignored
- Light entity shows color_temp_kelvin as None in developer tools
- Automations setting color temperature fail silently
- LocalTuya lights are most commonly affected
- Some HACS integrations also broke due to mired removal
Recognize these? Here's what usually causes it.
Common Causes
- Home Assistant 2026.3 removed deprecated mired-based color temperature attributes
- ATTR_KELVIN and ATTR_COLOR_TEMP removed from light.turn_on service
- Integrations using the old mired API no longer pass color temperature values
- LocalTuya library had not migrated to the new kelvin-only API
- Custom integrations using SUPPORT_COLOR_TEMP flag broke
- The change was deprecated since late 2024 but many integrations did not update
Most fixes happen in the first 3 steps.
Downgrading Home Assistant to restore mired support is a temporary fix. The deprecated attributes will not come back and integrations need to migrate eventually.
Step-by-Step Solution
Confirm the color temperature issue
Go to Developer Tools > States and find one of your affected light entities. Check the attributes. If you see color_temp_kelvin: None or the color_temp attribute is missing entirely, you are hitting this issue. Also try calling the light.turn_on service from Developer Tools > Services with color_temp_kelvin set to a value like 3000. If the light turns on but the color temperature does not change, the integration is not passing the kelvin value through to the device.
Update LocalTuya if that is your integration
The LocalTuya maintainers released a fix in pull request 2187 that migrates the integration to use color_temp_kelvin instead of the deprecated mired attributes. Go to HACS > Integrations > LocalTuya and check for updates. Update to the latest version and restart Home Assistant. After restart, your LocalTuya lights should respond to color temperature changes again. If no update is available in HACS, you may need to install the fix manually from the GitHub repository.
Update other HACS light integrations
Any HACS integration that controls lights with color temperature might be affected. Go to HACS > Integrations and check every light-related integration for updates. Common affected integrations include localtuya, tuya-local, flux_led, and various manufacturer-specific HACS integrations. Update all of them and restart Home Assistant. If an integration has no update available, check its GitHub issues page — there may be a beta or development branch with the fix.
Fix automations using mired values
If you have automations that call light.turn_on with color_temp in mireds, those need updating. Mireds and kelvin are inversely related: kelvin equals 1000000 divided by mireds. So 250 mireds equals 4000K and 400 mireds equals 2500K. Replace color_temp with color_temp_kelvin in your automation YAML and convert the values. The community has created a migration tool posted on the Home Assistant forums that can scan your automations.yaml and suggest the conversions.
Verify all lights respond to color temperature
After updating integrations and automations, test each light individually. Go to the light entity in your dashboard, and move the color temperature slider from warm to cool. The light should physically change color temperature. Check the entity attributes in Developer Tools to confirm color_temp_kelvin shows the correct value. If some lights still do not respond, those specific integrations may not have a fix yet and you will need to check their GitHub repositories or consider alternative integrations.
Quick Solutions
Still having issues? This is usually the deeper cause below.
Schedules that skip randomly are usually a daylight-saving holdover — delete and recreate the schedule to clear the corrupted entry.
The mired-to-kelvin conversion formula is simple: kelvin = 1000000 / mireds. Bookmark this for when you need to convert automation values. Common values: 153 mireds = 6536K (cool), 500 mireds = 2000K (warm).
Thermostat issues that keep returning are often caused by stale backup-battery memory holding old settings across power cycles without the user realising.
- Home Assistant 2026.3 removed deprecated mired-based color temperature attributes
- ATTR_KELVIN and ATTR_COLOR_TEMP removed from light.turn_on service
- Integrations using the old mired API no longer pass
- LocalTuya library had not migrated to the new kelvin-only
- Custom integrations using SUPPORT_COLOR_TEMP flag broke
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