When going out in a kayak it is always good to be prepared for all of the "what ifs"! A minimal safety kit might include a personal floatation device (PFD, lifejacket), a whistle on the PFD, spare take-apart paddle, a paddle float for self rescue, bilge pump, three flares, a light (headlamp or flashlight).

Additionally consider water, snacks, a spare warm and sun hat, extra clothes.

Moving on from there you can get really technical and get charts, a VHF radio, GPS...it all depends if you are going out on a warm protected lake for an hour, or on a more exposed trip.

Here in the Northwest we have the Puget Sound with cold water (we always wear non-cotton, protective clothing), with current and wind. The fun part is, no matter what the weather report is, you never know what will happen!