[TAP Air Portugal] Toronto (YYZ) to Terciera Island Azores (TER) via Lisbon March $440 Return
Fare is for carry on only so you'll pay extra for checked baggage.
Temperatures on Terciera are around 15 C during the day in March dropping to around 10 C at night.
I've heard it's not always easy to get accommodation so you may want to see what you can find on the net first.
TAP allows one to five days in Lisbon if you wish.
When doing a trial booking through Google Flights it said $429 return but then when clicking through to TAP the discount there brought it down to $409.
Depart YYZ Sunday March 29th. Arrive in Lisbon on Monday March 30th.
Depart LIS Thursday April 2nd and arrive on Terciera Island.
Depart TER on Thursday April 9th for LIS to get the connecting return flight to YYZ.