Croatia has its own weather. You need to know this, ECMWF, GFS and most other well known weather models will not work in Croatia.
There tends to be no wind or too much wind based on the Bora.
The Bora is caused by the predominate weather patterns building up behind the blocking hills that run all the way along the Croatian coast until they can’t be contained anymore and then spilling over and rushing down onto the coast and islands.
This often means the afternoon Katabatic winds will pull the pent up winds over onto the islands late afternoon as the sun starts to cool off. You can be motor-sailing in perfectly clear skies with not enough wind to fill your sails and glassy clear seas one minute and have 40kts of cool air hammering down onto you the next from NE to NW.
The Bora, once it arrives will last from an hour or two to 12 hours and build exceptionally quickly.
DHMZ is the local forecast site that can be trusted. I would add 10kts to the forecast and if its NE-NW later in the day, expect a BORA.