Listed among the marinas is Eilat. This marina is located at the Southern resort city of Eilat and is not on the Med coast.
Weather along the Israel coast is fairly predictable. That is to say, the summer weather pattern usually begins with early morning winds from the East which clock around all day until the evening when they come from the Northeast. This means that most of the day you have sea breezes which make for nice sailing in 1 meter waves. This pattern can continue into November, which means great sailing from March to December.
The Winter pattern is not as predictable, but you can check the forecast for winds and wave heights. Things can get nasty. So nasty, that in 2003, a cruise ship carrying Egyptian tourists from Lebanon to Egypt was forced to run for Haifa to get out of 25 foot (steep) seas. The tourists were as nervous about pulling into an Israeli port as they were about the sea, but soon found a warm reception and hot food waiting for them as they rode out the storm in Haifa.
I personally have seen waves break over the jetty in Ashkelon and Herzliya during 2 - 3 day storms that lashed the coast. The waves were easily 25 feet plus, and no sane skipper would head out or be out in such conditions. Getting out of the marina would be impossible, and the short, steep waves along the coast would be very dangerous if not impossible.
Sometimes conditions can change (even in the spring or fall) in several hours. A few years ago, after arriving in Ashkelon at midnight (from Herzliya), I awoke to find 10 - 12 foot seas. The prior evening they were 2 - 3 feet. We chose to head back to Herzliya and found the conditions to be ok, but again, the Med can produce short, steep waves, and these were no exception. Upon making the turn into Herzliya 5 hours later, we caught a 10 footer plus on the stern of Sea Belle and surfed like driftwood parallel to the entrance of the marina. A quick turn got me behind the jetty before the next large wave rolled in...timing is important!
For the most part there aren't too many boats out around Ashkelon, whereas Tel Aviv and Herzliya are pretty busy for small boats.
What about trips?
Well, I must say that sailing out of Ashkelon in the South is pretty great. A nice trip is where we usually leave Ashkelon in the morning and sail to Herzliya. It's about 5- 6 hours plus tacking if the wind isn't right (not unusual). On the way, you pass one of my favorite places, the Port at Ashdod. There you sailing in between massive cargo ships all anchored off Ashdod. The kids LOVE this, as we sail past the big ships. Then it's up the coast past the ancient port of Yafo, past the modern Tel Aviv skyline, and another 8 miles or so to Herzliya.
Marina Herzliya is now surrounded by a large and beautiful shopping mall which houses nice stores and a movie theater. There are lots of restaurents nearby, and a very active night-life. It makes sense to call ahead to the marina and make arrangements to tie up along the "A" pier. This is where larger working boats occasionally tie up, so be sure to NOT tie up where it looks like these boats might show up...the best thing is to ask or to pull in close to the marina restaurent. The only problems there are the rubbish that tends to float on the water near the restaurent, and the fact that the public can often walk up and down this pier since the gate is often left open.