From the 30’s on a lot of radio stations would say “At the tone the time will be x” there would be a pause then a tone and you knew what time it was. Many towns would sound a whistle or siren when it was noon, (some small town still do this today), before that the railroad, from about 1865 on had clocks that could be synchronize from a signal sent out over telegraph wires (later they would set automatically), also many jewelry shops also got their time that way. Railroad at the time had rules required, you to reset your watch if it wasn’t with 30 seconds of the official time. That service remained in service into the 1970’s.
I had no idea about the syncing of clocks via telegraph. That’s very cool!
These days it’s not hard to find a clock that receives signals from Fort Collins.
I have listened to WWV. CHU out of Canada also gives (or at least they did a few years ago when I picked them up) the time, and, iirc, has a pulse tone signal that you can program a computer to receive and decode.
I do remember that the 1980’s were a bit more relaxed as to syncing times. Nowadays, people actually care if you are 5mins late. Back then, people’s watches could easily be 5-10 minutes off and people didn’t really seem to care. Now, everyone has cell phones that autosync.
In the days of yore (basically, before large mechanical clocks were common), water clocks and similar things did exist. But they weren’t so important. People had a pretty good sense of time naturally (though they didn’t always use the 12 hour day we do) and didn’t need to be on the hour so much. In many ways, we’re so worried about time because we can be; before clocks were everywhere, businesses had pretty flexible hours and people didn’t worry so much about it. Of course, it helped that people often lived right around the business, too.
Others have pretty well explained the use of time after that.
We still have ours (Cape Town) - and a noon gun.
Sir Sanford Fleming was the inventor of Standard Time (hence the “sir”). Before that, every town would sync their time to whatever method was convenient - the local town hall clock, church clock/bells, etc.
IIRC the Romans used various mechanisms, especially sundials. the day was divided into 12 hours, which varied depending on season/length of day.
Remember that ITGOD (in the good old days), europeans had a habit of saying the prayers on the hours, or at least morning, noon and night. Hence, the local church bells would ring out vespers, nooners, etc. so the locals could say their prayers. Whatever method they guy in charge of the bells used - water clock, sundial, mechanical clock - he was the one who decided for the town what time it was.
As time marched on and the need for more precise timekeeping became a necessity of life for urban dwellers, the church or town hall would put a mechanical clock in the tall tower so the hourly (then quarter-hourly) bells could be head all over town. Some european towns still have the remarkably precise clocks with elaborate mechanical displays every hour. The discovery of the pendulum principle - swing time proportional to length - allowed the construction of precise clocks.
Of course, mechanical clocks did not care about day or night, so an hour came to be an equal amount of time, regardless of sun position in the sky.
Each town had and set their own time, generally based on the position of the sun or the sobrietty of the master timekeeper… It did not matter that you were off by a few minutes when it took hours or days walking or horseback to get from one town to the next.
The first major requirement for timekeeping was the search for the key to determining longitude, that came about with the wide-ranging nautical explorations in the 1500’s and later. The best system required a precise clock, not affected by the wave actions on the pendulum (hence, spring-driven clocks). If you know what time it is in Greenwich and your latitude, see what time the sun rises where you are and you have a pretty good idea of where you are. So the Greenwich time meridain (0 degrees and Greenwich mean time) became a constant for sailors.
(SPOILER - the search for Red Rackham’s island in Tintin’s Red Rackham’s Treasure hinges based on the fact that Tintin/Haddock/Rackham was French (Belgian?) and used the Paris Meridian, which in the 1600’s and 1700’s was not unusual. So they were looking at the wrong coordinates. Standardization…)
The need for standard time arose by the mid-1800’s, as the railroad age got going. Trains had to arrive and leave on time. This was precision to the nearest few minutes, and likely someone would go from one town to another in one tenth the time they used to. Pocket watches were also common. As an earlier post points out, you could use the telegraph with it’s pretty much instantaneous nature to set station clocks. (And a lot of older stations had their own clock towers…!) By the railroad era, telegraphs were part of the infrastructure too.
Similarly, as factories became the work norm, the need for everyone to show up on time, have lunch at the same time, and quit all together meant the need for precise timekeeping.
So the short answer is, by the time that time mattered, there were businesses like the railroads that had pretty precise clocks on public display. Plus, if anyone remembers cheap watches from 40 plus years ago…A watch that could keep time within seconds a day without a lot of fiddling and adjustment was either Rolex-expensive or a pipe dream. You reset your watch every day or two to the official time, learned how much it drifted each day and adjusted, waited for the church bells to verify time… Places like factories that needed precise time bought expensive reliable clocks and verified the time as required. Set your watch on the way past the railroad station, then set the factory time-clock from that was pretty much sufficient until radio beep signals became common.
Necessity is the mother of invention.
JJY is a Japanese time signal station that has been going for half a century. CHU in Canada is slightly older. WWV in the USA is 90 years old and the oldest continuous radio station using the same callsign in the USA
Knowledge of the time has long been very important for celestial navigation at sea, as the error in your longitude basically scales with the error of your timepiece. (It’s not your local time that you need for this - it’s some global reference time.) Latitude, by comparison, is easy to determine.
When a reliable marine chronometer was developed in the 1700’s, it was a big deal. That wiki page quotes:
Isn’t that still true? It’s easier to get a more precise time now, but I don’t really need it.
My dad had a multi-band radio that picked WWV the official time channel. Plus we could call time/temp by phone. Which we still do. It’s on my speed dial. 
md2000, that was a great post.
I highly recommend a book called Longitude. It was made into a made-for-TV movie starring Jeremy Irons, but I have no idea if it’s any good.
Side note: In the English version of the song, Brother John has to get up because the matins (morning bells) were ringing. In the original French version, though, Frere Jacques has to get up because he’s the one who’s supposed to be ringing the matins.
In California at least, the phone number to get the time was “767-####”, but usually remembered as “POP-CORN” (any four numbers after 767 worked). The service was discontinued in 2007. http://redwoodtech.org/there-no-more-popcorn-time
Growing up in Wisconsin I was a stickler about my watch being right and used to call the time number there too. It wasn’t POP-CORN though, and sadly that little bit of trivia is lost from my memory.
Then what is the point? 
It’s worth watching. It bounces back and forth between Harrison’s time (18th cen) and the 20th century efforts to restore his clocks and frankly I found the former scenes to be far more interesting. One of the first things I did when I had some time in London was to visit the Harrison display at Greenwich.
I got much of the trivia IIRC from a Daniel J Boorstin book (The Discoverers) that I read many years ago.
I suppose part of the problem with accuracy is our environment. When every clock is pretty much in sync (not quite there yet) then it is bad to be out of sync, even by a few minutes. I notice now, for example, when the clock on my car dashboard is off from official “beep” time on the radio. I do remember trying to keep a watch accurate that lost 5 minutes a week. Even my first digital watch lost 30 seconds a day. I have found PC’s whose internal clock wanders by minutes a month, if you don’t sync to a time server.
Normally, we don’t care about 5 minutes one way or the other; although the boss is usually upset if the 5 minutes is the wrong way. Stores that open at 9AM, the clerk might unlock a few minutes early or late.
However, when the train or airline says it will leave at 8:07 and the gates will close at 8:04, all the clocks in the station are probably sync’d to the exact time and and that’s pretty close to the exact time things will happen.
So as always, you find a source you expect to be accurate and set your watch to it.
It reminds me of the old joke: A man with one clock knows what time it is. A man with two clocks is never quite sure.
As a ham radio operator, the WWV transmitters also serve as handy beacons to help indicate the current shortwave signal propagation characteristics. The stations are on some easy-to-remember channels: 2.5, 5, 10, 15 & 20MHz.
That’s how we did it as a kid; Dad would rig up the Heathkit shortwave and we’d tune in and set the clocks every so often.
I imagine pre-shortwave, people’d set their watches to the clock on some public building like the courthouse, which presumably, was set to something else somewhere by some reasonably accurate timepiece.
The Royal Observatory exhibits on timekeeping were much, much more fascinating than I expected them to be; I’d made the trip to Greenwich to see the Cutty Sark and the NMM, and just trudged up the hill to see the Prime Meridian. I went through the exhibits on a whim, and they turned out to be the coolest thing I saw that day.
Huh. When I was growing up in Riverside, CA in the 70’s and 80’s, it was 853-####.