# Car clocks automatically updating to Daylight Saving Time **URL:** \ **Category:** Factual Questions\ **Created:** [March 12, 2024, 8:25pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769 "2024-03-12T20:25:33Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Briny\_Deep](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/briny_deep/32/17188_2.png) [@Briny\_Deep](https://boards.straightdope.com/u/Briny_Deep)\ **Post date:** [March 12, 2024, 8:25pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/1 "2024-03-12T20:25:33Z")
I’ve had my 2014 Impala for several years, and the same thing happens every spring and every fall: the car’s clock doesn’t know the time changed, and then after a variable amount of time (days to weeks), it belatedly figures it out and updates itself. Why would this be? My guess is it’s getting a signal but perhaps not getting that signal in my driveway; maybe I have to go into town for it to receive the news. I live in pretty well developed suburbia and go into a large city every week. I have not yet been into town this week, since the time changed on Sunday. I have no paid satellite services like Sirius radio, etc., and the car is never connected to any phone (that I know about). One idea: when I turn on the radio, there’s a message “acquiring HD signal” for several seconds. The thing is, I almost never turn on the radio. Maybe that’s the event that reminds the clock to update? I’ll check that next time I’m in the car. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [March 12, 2024, 8:43pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/2 "2024-03-12T20:43:51Z")
> [@Briny\_Deep](#): > > after a variable amount of time (days to weeks), it belatedly figures it out and updates itself How many weeks? 25ish? Seriously, though, are you CERTAIN it isn’t someone else changing the clock. ---
**Author:** ![Briny\_Deep](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/briny_deep/32/17188_2.png) [@Briny\_Deep](https://boards.straightdope.com/u/Briny_Deep)\ **Post date:** [March 12, 2024, 8:47pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/3 "2024-03-12T20:47:37Z")
Maybe 2 or 3 weeks is the longest it’s ever taken. Almost but not quite long enough for me to get sufficiently annoyed to look up how to change the time manually. Am I certain it’s not somebody else changing the clock? Like, my partner gets fed up with the wrong time sooner than I do, and fixes the clock without telling me? I guess it could happen, but really, no. ---
**Author:** ![a6ka97](https://avatars.discourse-cdn.com/v4/letter/a/c2a13f/32.png) [@a6ka97](https://boards.straightdope.com/u/a6ka97)\ **Post date:** [March 12, 2024, 8:49pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/4 "2024-03-12T20:49:14Z")
A few years ago wasn’t the date for daylight saving time changed? Maybe your car is programmed for the old date? ---
**Author:** ![Briny\_Deep](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/briny_deep/32/17188_2.png) [@Briny\_Deep](https://boards.straightdope.com/u/Briny_Deep)\ **Post date:** [March 12, 2024, 8:54pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/5 "2024-03-12T20:54:10Z")
It’s been the 2nd Sunday in March since before the car was manufactured. Now I’m wondering, does the car know when it’s the second Sunday in March, or did they just program “Eh, March 12 every year, close enough”? Again I would have thought it got a time signal from somewhere, so the dashboard clock doesn’t have to know what the date is, let alone what the time actually is. Maybe I’m imagining it’s all higher-tech than it actually is. ---
**Author:** ![hende](https://avatars.discourse-cdn.com/v4/letter/h/aca169/32.png) [@hende](https://boards.straightdope.com/u/hende)\ **Post date:** [March 12, 2024, 9:13pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/6 "2024-03-12T21:13:37Z")
Depending on the car and manufacturer, there could be a number of ways a car clock gets updated automatically. - RDS data from radio broadcasts - Cellular data - GPS data - Pre-programmed into the car’s infotainment system ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [March 12, 2024, 9:15pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/7 "2024-03-12T21:15:05Z")
> [@Briny\_Deep](#): > > Like, my partner gets fed up with the wrong time sooner than I do, and fixes the clock without telling me? I guess it could happen, but really, no. I got five on it. You could set it incorrectly today and, with your detailed journal entries and spreadsheets, see what happens over the coming weeks. ---
**Author:** ![hogarth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hogarth/32/1773_2.png) [@hogarth](https://boards.straightdope.com/u/hogarth)\ **Post date:** [March 12, 2024, 9:18pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/8 "2024-03-12T21:18:01Z")
I have a fairly primitive clock-radio that can nevertheless detect when it’s daylight saving time and it will reset the time after a power outage. But I believe the factory settings for the clock are off by ~25 hours, so the clock keeps resetting to be one hour fast and one day off in terms of DST. I seem to recall seeing a web page that claimed that it’s theoretically possible to change the clock-radio’s settings, but it didn’t seem worth the bother. ---
**Author:** ![AlsoNamedBort](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alsonamedbort/32/3213_2.png) [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)\ **Post date:** [March 12, 2024, 9:24pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/9 "2024-03-12T21:24:44Z")
Looking around, it looks like Chevy’s update DST based on cell data. With all the changes to networks over the past decade, I’m guessing it’s not picking up the right signal to update the clock until it gets close enough to a certain tower. ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [March 12, 2024, 9:50pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/10 "2024-03-12T21:50:33Z")
2013 Honda here, have to manually change it twice a year. ---
**Author:** ![Seanette](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/seanette/32/9139_2.png) [@Seanette](https://boards.straightdope.com/u/Seanette)\ **Post date:** [March 12, 2024, 9:53pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/11 "2024-03-12T21:53:30Z")
My 2016 Dodge Dart does not auto-update. We have to do it (tends to involve digging out the manual). ---
**Author:** ![Folly](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folly/32/3219_2.png) [@Folly](https://boards.straightdope.com/u/Folly)\ **Post date:** [March 12, 2024, 11:49pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/12 "2024-03-12T23:49:50Z")
> [@Briny\_Deep](#): > > It’s been the 2nd Sunday in March since before the car was manufactured. Wow. It changed in 2007 for the record. If I had guessed without looking it up I would have been quite a few years off. Like 2015 or something. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [March 13, 2024, 3:24am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/13 "2024-03-13T03:24:18Z")
You must be as old as me. “A few years ago” was 2007. ---
**Author:** ![Retzbu\_Tox](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/retzbu_tox/32/11829_2.png) [@Retzbu\_Tox](https://boards.straightdope.com/u/Retzbu_Tox)\ **Post date:** [March 13, 2024, 11:58pm UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/14 "2024-03-13T23:58:47Z")
My 2014 Chevy Silverado has successfully reset its clock on its own for the last few years, based on cell tower signals, I think. This time, it failed to do so, and I had to do it manually. Perhaps backward compatibility has not been maintained on new 5G cell towers, and the current time signal is not detectable by my 10 year old truck? ---
**Author:** ![Spiderman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiderman/32/230_2.png) [@Spiderman](https://boards.straightdope.com/u/Spiderman)\ **Post date:** [March 14, 2024, 12:49am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/15 "2024-03-14T00:49:59Z")
The 3g cell signals were shut down last year. If you have an older GM car, OnStar will no longer work because it was running on 3g. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [March 14, 2024, 1:07am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/16 "2024-03-14T01:07:29Z")
> [@Retzbu\_Tox](#): > > Perhaps backward compatibility has not been maintained on new 5G cell towers The 5G service will have the capability. But a 2014 truck won’t be able to talk to 5G. So if the 3/4G has gone, and your truck was using it, your truck won’t be able to update. Indeed it will be feeling very alone. For a lot of cars my bet would be on using RDS data. So would depend on using the radio and listening to a RDS source. GPS is great for a superb quality time sync, but it only provides UTC. The device still needs to know what, if any, local offsets are in play. That doesn’t come with the GPS signal. ---
**Author:** ![phs3](https://avatars.discourse-cdn.com/v4/letter/p/8491ac/32.png) [@phs3](https://boards.straightdope.com/u/phs3)\ **Post date:** [March 14, 2024, 1:07am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/17 "2024-03-14T01:07:54Z")
We have a bedside radio that does it automatically–but using the old dates. And you can’t disable the feature (sorry, Arizonans!). So now I have to change it FOUR times a year, because it’s on my wife’s side of the bed. Grr. And yes, she likes the clock otherwise, and no, they don’t sell an updated model. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [March 14, 2024, 1:16am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/18 "2024-03-14T01:16:36Z")
A bazillion years ago I was involved in a computer design project. We wanted a real time clock chip, and there was a common one from Texas Instruments. Looked great. There was a DST capability. Reading the documentation it turned out that it hard wired the dates. It worked perfectly if you were in Texas in the 1980s. Over here in Australia, not so well. ---
**Author:** ![Briny\_Deep](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/briny_deep/32/17188_2.png) [@Briny\_Deep](https://boards.straightdope.com/u/Briny_Deep)\ **Post date:** [March 14, 2024, 1:29am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/19 "2024-03-14T01:29:59Z")
> [@Francis\_Vaughan](#): > > > [@Retzbu\_Tox](#): > > > > Perhaps backward compatibility has not been maintained on new 5G cell towers > > The 5G service will have the capability. But a 2014 truck won’t be able to talk to 5G. So if the 3/4G has gone, and your truck was using it, your truck won’t be able to update. Indeed it will be feeling very alone. This makes sense. Perhaps my car, also a 2014 Chevrolet like Retzbu\_Tox’s truck, is feeling alone waiting for a 3G signal that will never come. A melancholy thought, and probably a symbol of something. > [@Francis\_Vaughan](#): > > For a lot of cars my bet would be on using RDS data. So would depend on using the radio and listening to a RDS source. So wait – are you saying that maybe just turning on the radio, a rare event for me, could be what clues the car in? ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [March 14, 2024, 1:32am UTC](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769/20 "2024-03-14T01:32:50Z")
> [@Briny\_Deep](#): > > So wait – are you saying that maybe just turning on the radio, a rare event for me, could be what clues the car in? Yup. This would be my top bet. A lot depends on the system integration, but many cars have integration of stuff in odd ways. [Next page](https://boards.straightdope.com/t/car-clocks-automatically-updating-to-daylight-saving-time/998769.md?page=2)