How many letters does the top answer for “pertaining to or occurring in the morning” have?

The most common answer is matutinal (9 letters).

Crossword clue: pertaining to or occurring in the morning

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

matutinal 9 letters wn-def

pertaining to or occurring in the morning

of or pertaining to the morning; early. 50% similar → matutinal