Has the name Knut been retired?
Yes. Knut is on NHC’s list of retired eastern and central Pacific names because of the 1987 storm. It is one of 22 names retired there since 1965 (Tropical Cyclone Naming History and Retired Names).
A name is retired when a storm was so deadly or costly that using the name again would be insensitive; the World Meteorological Organization then picks a new name with the same first letter at its annual meeting.
When will Knut be used again?
It won’t be. Retired names are not used again on the eastern and central Pacific lists. Its place on the list, the K slot, now belongs to Kenneth, on the 2029 East Pacific list, which is next used in 2029.
Why was the storm named Knut?
Names go in alphabetical order, one per storm, as each storm reaches tropical-storm strength (39 mph, 34 knots), so a storm’s place in its season decides its name.
In both 1987 and 1981, Knut was the 11th name used in the East Pacific season.