# When does the display switch between Day and Night Mode?



## GDN (Oct 30, 2017)

[mod note: discussion forked from the 2019.16 firmware thread]



JulienParis86 said:


> Would be great if in "auto", Night mode can be activated when entering in a dark environment (tunnel, parking...)


One thing I've noticed for sure, US cars the screen change (from day to night mode) is not tied to the auto headlights. The auto headlights operate on a totally different sensor than the screen. In fact, the screen almost seems to operate on a time based schedule. I'd much rather it do as you note and respond to a light sensor in the car. I know there is one because it can auto dim based on light, but a total switch from day to night mode and vice versa truly seems to happen at a given time of day based on sunrise/sunset.


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## MelindaV (Apr 2, 2016)

GDN said:


> One thing I've noticed for sure, US cars the screen change (from day to night mode) is not tied to the auto headlights. The auto headlights operate on a totally different sensor than the screen. In fact, the screen almost seems to operate on a time based schedule. I'd much rather it do as you note and respond to a light sensor in the car. I know there is one because it can auto dim based on light, but a total switch from day to night mode and vice versa truly seems to happen at a given time of day based on sunrise/sunset.


not only different than the headlight schedule, but also the auto dimming mirror's schedule


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## Mike (Apr 4, 2016)

GDN said:


> One thing I've noticed for sure, US cars the screen change (from day to night mode) is not tied to the auto headlights. The auto headlights operate on a totally different sensor than the screen. In fact, the screen almost seems to operate on a time based schedule. I'd much rather it do as you note and respond to a light sensor in the car. I know there is one because it can auto dim based on light, but a total switch from day to night mode and vice versa truly seems to happen at a given time of day based on sunrise/sunset.


I'd guess it's GPS based and either at sun set (corrected for atmospheric refraction) or a fixed time between sunset and what used to be known as "civil" twilight (center of the disc of the sun is six degrees below the observer's horizon).


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## JWardell (May 9, 2016)

Mike said:


> I'd guess it's GPS based and either at sun set (corrected for atmospheric refraction) or a fixed time between sunset and what used to be known as "civil" twilight (center of the disc of the sun is six degrees below the observer's horizon).


Yes, the computer flips the computer via time and GPS...it actually calculates the angle of the sun


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## Rick Steinwand (May 19, 2018)

JWardell said:


> Yes, the computer flips the computer via time and GPS...it actually calculates the angle of the sun


Even if you're driving on Mars.


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## JWardell (May 9, 2016)

Rick Steinwand said:


> Even if you're driving on Mars.


There's no GPS satellites on mars...._yet_.
(I think I just discovered Elon's real purpose behind Starlink...)


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## Nautilus (Oct 10, 2018)

I happened to notice on my (late) drive home today that the control screen went to dark mode at 8:53pm. Local time of sunset today according to the Weatherbug app was 8:58pm, so 5 minutes before sunset. I'll have to see if I can get a couple more datapoints. I am still on 2019.12.1.2.


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## Bokonon (Apr 13, 2017)

Nautilus said:


> I happened to notice on my (late) drive home today that the control screen went to dark mode at 8:53pm. Local time of sunset today according to the Weatherbug app was 8:58pm, so 5 minutes before sunset. I'll have to see if I can get a couple more datapoints. I am still on 2019.12.1.2.


There was a similar discussion over in the auto-dimming mirror thread a few months ago when we were trying to figure out when the mirrors dimmed. It seemed like the screen flipped over to night mode at sunset, and then the mirrors dimmed at the end of civil twilight.


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## GDN (Oct 30, 2017)

On my way to work this morning the screen flipped from night mode to day mode at 6:27 AM, Dallas, TX. According to the weather channel Sunrise is at 6:23 AM here this morning. Headlights remained on. Did not note any changes to rear view mirror, wasn't really thinking about it.


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## Kizzy (Jul 25, 2016)

Nautilus said:


> I happened to notice on my (late) drive home today that the control screen went to dark mode at 8:53pm. Local time of sunset today according to the Weatherbug app was 8:58pm, so 5 minutes before sunset. I'll have to see if I can get a couple more datapoints. I am still on 2019.12.1.2.


Just now, screen switched to night mode at 8:13pm. Reported local sunset time was 8:18pm (via Weather Underground). So, also 5 minutes before sunset. (This is also on 2019.12.1.2.)


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## Nautilus (Oct 10, 2018)

Kizzy said:


> Just now, screen switched to night mode at 8:13pm. Reported local sunset time was 8:18pm (via Weather Underground). So, also 5 minutes before sunset. (This is also on 2019.12.1.2.)


And I was driving home from an event Saturday evening and the screen switched again at 5 minutes before local sunset time, so I think we have this pattern nailed.


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