Most affiliates for ABC, CBS and NBC air local news from 4 or 430am to 7am - then go to the national shows: GMA, CBS Mornings and NBC Today. All 3 of these have two x 3 minute windows every hour for local stations to insert local news. It seems to happen at about :25 and :55 past the hour I recall. All stations do this from huge markets like NYC (18 million people) down to markets the size of say Tasmania (500,000) It’s normally a mix of live local news, weather and traffic with lots of live cams showing the city and surrounds (not unlike Sunrise is doing)
FOX stations in most markets (probably. the top 150 largest or so) have local news shows that more often than not run from 430 or 5am and through to 9am or 10am. They tend to be "Good Day (City) or “Good Morning (City)”
Then CW affiliates in larger markets (probably the top 50 or so in size) also have local news shows from 4/5or 6am than run through to 9am.
More often than not across the US (and certainly In large markets like NYC, LA, Chicago, Philly, Dallas - the largest 5 markets) the #1 most watched morning show between 7am and 9am tends to be the FOX local show, or sometimes the CW local morning show. The network shows are more often than not number 1 in each market, people prefer the local show.
In NYC it is Fox5’s “Good Day New York” that is #1. In LA it’s the “KTLA Morning News” on the CW affiliate which has been #1 for a decade. The #1 show in Chicago is actually on an independent station; WGN Channel 9 - not network affiliate. Their “WGN Morning News:” is #1 there.
In market #4 Philadelphia - the #1 show is Fox29’s “Good Day Philadelphia”
Some mid sized markets have the network shows GMA, Today or CBS Mornings as the #1 show. But then as you get into smaller markets again - under 1 million - they are more parochial and again the local morning shows are tops.
In the US also another thing that is weird is the station that has the #1 most watched 6pm newscast, tends to NOT be #1 at 11pm too - it’s a different station (often the one that wins primetime and provides a good lead in)
In LA and NYC the dominant local news at 6 is the local ABC station: ABC7. CBS is often 3rd of even 4th behind Fox.
Most Fox stations run TMZ or sitcom repeats or game shows at 6. But more and more and doing local news at 6 now, following on from local news at 5