Ok, so you are in Southern California, but don’t let that fool you! It can get cold on Catalina Island, especially at night and during the winter. You will be swimming, most likely, or at least getting wet in the kayak, which will make you colder.
For the most part, its going to be sunny and warm during the summer. The daily average temperature from April – October is between 55F – 70F. However, the weather can change rapidly, and it is difficult to predict. The prevailing wind is generally from the NW, parallel to the island. When you are paddling from Avalon -> North, you are paddling into the wind and “uphill.” When you are paddling South towards Avalon, you are paddling with the wind and “downhill.”
Getting an early start for any kayaking is always a good idea on Catalina as the currents/waves are not as powerful (even though on the leeward side of the island they generally are not a concern any way) and the wind has not yet picked up. During winter, you can get extreme winds, so make sure you have your tents and gear staked down while camping. Also, while the currents are generally not too strong (except somewhat during new moon phases), you will experience stronger currents and larger waves anytime there are jutting rocks that are furthest points out of the island, such as Long Point and the West End.
Just make sure to bring a sleeping bag at night, warm clothes and a towel during the day in case the sun isn’t drying you off well enough, and a hat, sunglasses, and sunscreen during the day to keep the sun burns to a minimum!
Kayak Camping Catalina Island 