Often in hot summer weather, bees gather around the entrance porch of their hive to cool off. This is normal. It would also be normal to see 2-3 times as many bees as this. When this photo was taken, it was more than 90 degrees Fahrenheit in early evening. Bees pictured are calm and walking about. Some bees will fly in and out of the hive.
Sometimes beekeepers worry that this looks like swarming behavior, but is actually just cooling behavior.
Here's what the hive looked like inside. The box is not at capacity yet.
With swarming, there would be a large cluster of bees in late morning or early afternoon, with hundreds/thousands of bees pouring out of the entrance and a loud “buzzing” noise. Bees will be flying in circles around the hive and very active. They are usually not aggressive when swarming. Bees will come out all at once and fly away to hang in a cluster, like the one below.
Notice the difference in number of bees between this cluster and the cooling behavior photo above. This is a basketball-sized group of dense bees, all hanging on each other. There are tens of thousands of bees in the cluster.