This is the 10244th most frequent Polish word.
błyszczał
"Błyszczał" means "was shining" or "was glittering" in English.
The word "błyszczał" here describes the shining or glittering appearance of the watch in response to the light.
Kiedy wszedł do sali, jego zegarek błyszczał w świetle.
When he entered the room, his watch glittered in the light.
The usage of "błyszczał" in this sentence metaphorically describes the prominent and impressive display of the artist's talent.
Artysta błyszczał swoim talentem podczas występu.
The artist shone with his talent during the performance.
In this context, "błyszczało" is used to illustrate the clean and calm appearance of the post-storm sky, almost as if emitting light.