Summer, late May till late August. Water temp. summer ranges from 16-20°C. Air temp. from 18-25°C. Season from April until September. You prefer a wetsuit, 3/5mm. The best wave-surfing is in the winter: Oktober-March.
The wind is somewhat inconsistent, 60% kiteable days in the summer-season. Spring and fall can come up with very nice days, and rainstorms, in a one day "notice"...
There are airport-shuttles to Stavanger, with stops along the way. Let them know where you are going and they will tell you where to get a taxi. From Stavanger drive south towards Klepp. Get on R507 and drive westwards and find Bore and get to the beach.