What are the most accurate Quartz & Mechanical watches?

[Shawry9]

Whats acclaimed to be the most accurate quartz and mechanical watch? I’m interested in the below Grand Seiko spring drive (plated at +/- 15 sec per month however I understand this is more like +1 sec per month), being a hybrid of the two movements I’d like to see how it stands up against the best the original two can offer independently.

[Der Biermeister]

My new Grand Complication (Citizen Signature) has gained only 4 secs in 3 weeks. And the last few days, it seems to be holding at that.

[CitizenM]

I don't know about custom made watches, but the highest rated mechanical watch are Grand Seiko 9S models. The ordinary 9S65 and 9S85 are rated for an industry best +5/-3, and they make special 9S85 models that are rated for +4/-2. Of course, those are worst case scenarios and in real life they're a lot more accurate than that.

But there's luck of the draw in any given mechanical. I've had two mechanicals that beat most of my quartz watches (and they weren't rated especially well with accuracy). People have had great reports on the new Omega 8500 calibres, although they're officially rated for the standard COSC +6/-4.

But, as always, your mileage may vary when it comes to watches.

As per quartz, I don't think there's any dispute that The Citizen A660 Chronomaster is the most accurate model in the world, rated for 5 seconds a year. The new A010 may actually outperform it, but it's rated the same, so we'll just have to see.

[CitizenM]

As per spring drive watches, they're so accurate that anything better is irrelevant. Most people report under 3 seconds a month on SDs, which is just so little that I can't be bothered to care about things more accurate.

Remember, on MOST watches, if you adjust for daylight savings time, you will "hack" the seconds hand and have to reset it anyway, meaning that, in countries with daylight savings time equivalents (or when traveling to different time zones), the accuracy can only be relevant until you change the hour/timezone. So even if a watch is accurate to 1 second a year, if you have to pull the crown for DSL, you have to set it again anyway.

There are exceptions though. Most GMT watches, and the Citizen Chronomsater, have independently adjustable hour hands that don't stop the seconds. Also, all spring drive GMT models have independently adjustable hour hands.

[v76]

The Patek Philippe Seal guarantees a daily rate variation not exceeding +2 to -3s/day, this is tighter than the GS standard. And, I believe on the Tensus, Heritage Watch Manufactory assures the customer of a daily rate variation not exceeding +/-2s/day ... they claim that if it has properly been adjusted, it would be a lot less than +/-1s/day.

I don't know about custom made watches, but the highest rated mechanical watch are Grand Seiko 9S models. The ordinary 9S65 and 9S85 are rated for an industry best +5/-3, and they make special 9S85 models that are rated for +4/-2. Of course, those are worst case scenarios and in real life they're a lot more accurate than that.

But there's luck of the draw in any given mechanical. I've had two mechanicals that beat most of my quartz watches (and they weren't rated especially well with accuracy). People have had great reports on the new Omega 8500 calibres, although they're officially rated for the standard COSC +6/-4.

But, as always, your mileage may vary when it comes to watches.

As per quartz, I don't think there's any dispute that The Citizen A660 Chronomaster is the most accurate model in the world, rated for 5 seconds a year. The new A010 may actually outperform it, but it's rated the same, so we'll just have to see.

[Robbert1967]

SEIKO GRANDSEIKO SBGX061
This Grand seiko watch +/- 10 seconds a year and outstanding quality
Such a nice Quartz Timepiece.

[Shawry9]

SEIKO GRANDSEIKO SBGX061
This Grand seiko watch +/- 10 seconds a year and outstanding quality
Such a nice Quartz Timepiece.

I think this beats the Citizen Chronomaster on looks, interested if GS are being a little conservative on the +/- 10 sec a year (which they seem to be on the spring drive) would this match the +/-5 sec of the A660?

[Leonine]

Doesn't Bulova claim the most accurate quartz with their precisionist line?

[Robbert1967]

Bulova Precisionist is accurate to... 10 seconds... a year.
The Grand Seiko SBGX061 is also accurate to 10 seconds a year.
My Grand Seiko SBGT033 is accurate to 3.5 seconds a year.

[CitizenM]

The Patek Philippe Seal guarantees a daily rate variation not exceeding +2 to -3s/day, this is tighter than the GS standard. And, I believe on the Tensus, Heritage Watch Manufactory assures the customer of a daily rate variation not exceeding +/-2s/day ... they claim that if it has properly been adjusted, it would be a lot less than +/-1s/day.

The thing is, I'd rather have +4/-2 than +2/-3.