Tam,
Have just returned from Feurteventura 14 days ago and temp was in the 80's(28/29/30oC) for the previous 2 weeks so you should be okay. I'm sure it will be nowhere near 46 and anyway as you probably know there is always a fair breeze out there so it does not seem that hot.
Have fun...saw photos of Marlin,Sailfish etc but not sure how good the Big Game Fishing is...you done it over there before?
Richard