Set up the night light

The night light warms the screen's colors at night. It lives under [night-light]; the full setting list is in the night light reference.

Follow the sun

The default needs nothing written: schedule = "automatic" warms the screen from sunset to sunrise where you are. That needs your location, which glimpse gets from GeoClue, the system location service, or from coordinates you write yourself (see location). Without a location the screen stays neutral.

Keep fixed hours

[night-light]
schedule = "schedule"
start-time = "21:00"
end-time = "07:00"

Times are local, HH:MM. Both are required and must differ, and the window can cross midnight. With only one of them set, the night light stops changing the screen; glimpsectl night-light status says why.

Pick the warmth

temperature is the night color in Kelvin, from 1000 to 6500. Lower is warmer, and 6500 is the screen's own color. The default is 4200.

[night-light]
temperature = 3400

transition-minutes sets how long the change between day and night takes (15 by default). The change finishes at sunset or at start-time, so it starts that many minutes before. 0 changes over a few seconds instead of a full transition.

Change it for now

These commands never write the config file, and editing [night-light] or restarting the night light service drops all of them:

Command	Effect
glimpsectl night-light pause	keeps neutral daylight until the current night ends; refused during the day
glimpsectl night-light resume	ends a pause early
glimpsectl night-light temperature 3000	holds that temperature until the next sunset or sunrise, or your start-time or end-time
glimpsectl night-light temperature --clear	follows the schedule again
glimpsectl night-light schedule off	turns it off; automatic or schedule forces those instead

Check what it is doing

glimpsectl night-light status

It prints the mode, the temperature in use and the night target. When the screen is not being changed, the serving line says why.

If the screen never warms

Your compositor has to let clients set the display gamma, and only one program can do that at a time. Stop wlsunset or gammastep if one is running, then check glimpsectl night-light status. hyprsunset does not block glimpse, but it tints on top of glimpse, so the screen shows both.