Eh, that聮s not very helpful at all. And you聮re in California, with lots of sun and very warm weather.
Sun Precautions Solumbra Full Zip Cycle Shirt

But you raise a good point. Given current concerns over skin cancer and other sun-related problems, it makes sense that there would be long-sleeve cycling jerseys for warm weather, not just cool weather. Jersey makers, take note.
Fortunately, a few have. Sun Precautions makes just what you need: the Solumbra Full Zip Cycle Shirt ($89; sunprecautions.com). It聮s a cool, well-ventilated, long-sleeve jersey made from material with a 30+ SPF rating. It even has three deep back pockets, like any decent bike jersey should have.
A new brand in the United States, CW-X, also makes a sun-protective, light cycling jersey. Its Long Sleeve Team Cycling Jersey ($90; available at paragonsports.com) uses three different high-tech fabrics that cool, protect, and stretch so you聮re comfortable even on hot days. Its design is a little more elaborate than the lemon-yellow Sun Precautions shirt. But, try one of each.
Personally, I find it hard to believe that you sweat so much on your arms that you wash off all sunscreen. I think you聮d be fine oiling up with All Terrain AquaSport Sunscreen SPF 30+ ($10; allterrainco.com), and throwing the tube in your jersey pocket for a second coat. That stuff is really tenacious and should get you through a three-hour ride, keeping you cool and your dermatologist happy.
Get a sneak peak of 国产吃瓜黑料聮s picks for . The complete 2007 Buyer聮s Guide, featuring 400-plus gear reviews of this summer聮s must haves, is coming soon to 国产吃瓜黑料Online.