1. In accordance with the season
   "it was seasonably cold" 
2. At an opportune time
   - timely, well-timed, apropos

See also: seasonable

Antonym: unseasonably

• smashing
• smashingly
• smatter
• smattering
• SME
• smear
• smear campaign
• smear test
• smear word
• smeary
• smectite
• smegma
• smell
• smell a rat
• smell out
• smell up
• smeller
• smelling
• smelling bottle
• smelling salts
• smelly
• smelt
• smelter
• smeltery
• smetana