timely vs seasonably

timely is an adjective but seasonably is not an adjective.

Word	Noun	Adjective	Verb	Adverb
timely	No	Yes	No	Yes
seasonably	No	No	No	Yes

As adverbs, timely and seasonably are synonyms defined as:

Other synonyms of timely include apropos, well-timed.

timely (adjective)	seasonably (adjective)
done or happening at the appropriate or proper time
before a time limit expires

timely (adverb)	seasonably (adverb)
at an opportune time	at an opportune time
	in accordance with the season