How are "Moments" defined in Photos for Mac?

They are not all grouped by the same date though. There are some multiple groupings on the same date, usually split by location (which is logical) but also sometimes by time (e.g. some morning photos are grouped together, as are some evening ones). It's those parameters around time and location which I am curious about- i.e. what rules are applied to group the photos.

But I have some photos that are grouped together despite different locations and, conversely, some photos from the same location on the same day split into two moments.

Hence, presumably there are rules being applied that aren't just to group photos by day (or time?) and/or location?

Yes, that's the point of my post. To ask if anybody knows what the rules might be, or can guess them from their experiences (as I am unable to from mine).

I have photos in my library from more than one device - and therefore at the same time in different locations - and Photos is grouping them altogether despite being at different locations.

My preference is to separate Photos by location and time, but as the Photos view is chronological presumably time is the priority rule.

I'm still not clear what rule it is then applied to time - some collections of moments are over two days, others are only a morning (despite all being at the same location).

My situation should be more straightforward than yours léonie, as I'm based in the UK where we have the same time zone (so time zone shouldn't be a significant issue).

The only exceptions are when I go on holiday but this is relatively easy to manage as there is a defined time period I'm away from the UK and those photos are rarely mixed with different time zones.

Because I have photos from more than one device/family member in my library, I'm getting moments bunched together in different UK locations when I think they should be separate (as they are - in UK terms - relatively far away). Presumably this is because Photos doesn't want to break its chronological order and, if it split out photos for every different location, then it would be displaying multiple moments. Instead it appears takes a call to group together all the photos, say in a morning, even if they are from three or four different locations.

Yes they all have GPS and I've just been through the painstaking process of adding GPS to photos where there was no location.

I even have this issue with photos taken on the same phone. For example, I have a number of shots in the day in London, and then a single shot from 120 miles away that evening. All photos are grouped together in the same moment with two locations listed.

I actually think Moments is a good addition to Photos but, as with much of Photos, it doesn't quite work 100% how one would expect it to.