Norway in August

Define "good".

There are many possible options. It's hard to come up with suggestions without knowing a bit more about your trip.

Yes, more information needed.

How long? Will you have a car or rely on public transportation? How many and ages????

What are you hoping to experience?

And what's your budget ?

"Base location" sounds as if you may want to spend all your nights in one place. I wouldn't plan to do that. Norway's geography is challenging; it doesn't lend itself to a hub-and-spoke trip.

We did a fantastic cruise up the coast of Norway to the North Cape. Stopped at 6 ports, it was with Royal Caribbean. NCL also has a similar cruise.

We just came back from Norway...
Norway is so unique and has so many different amazing places, I wouldn't have any "base" locations.

We rented a car, and just drove from one place to another.. staying in one night in each locations. example.. one day near Pulpit Rock, one day near Flam, one day near Glacier Park, two days in Geiranger, etc...

don't lock yourself into just one base location... expand horizons..

My family has spent time in Norway in August. Hard to have a "base" in my opinion, I might suggest breaking up your trip with a few days/nights in different locales depending on interest. We stayed in Oslo for several days then did the Norway train & ferry trip through the Sogneford. We stayed a night in Ballastrand as we wanted to experience a bit of life in the fjord area. From there the following day we departed via fast ferry to Bergen were we concluded our time with a few nights stay. Norway is so scenic we wanted to see things and not be the ones driving & navigating maps etc. potentially missing some of the great views. But it really depends on what you want to do and where in the country you want to spend your time.