SACRAMENTO—Sunny California will live up to its name for months yet, but when winter weather comes motorists will have to remember to comply with a new law that takes effect Friday.

The law requires drivers to turn on their headlights when they turn on their windshield wipers in rain, fog or snow.

Forget? It could mean a fine of up to $96.

The Department of Motor Vehicles says it will try to help motorists remember by adding the law to its driver’s handbook.

“With all the crazy weather we have had this year, don’t be surprised when an officer stops you in the middle of a rain storm, during sleet and snow or foggy conditions, for not having your headlights on,” California Highway Patrol Officer Kelly Baraga said in a statement.

Enforcement will be a bit of a judgment call, however, since lights must be on only when wipers are in continuous use, not if they’re used intermittently or if there is more than 1,000 feet of visibility.

The National Highway Traffic Safety Administration says using headlights can cut the risk of accidents. At least 28 other states have similar laws.

Among other laws taking effect with the July 1 start of the new fiscal year:

Health care and insurance companies must stop using Social Security numbers on health plan cards, mailings to patients, and anywhere else they might be available to identity thieves. The 2001 law gave the businesses until Friday to comply.

“It means millions of Californians will no longer be putting themselves at risk for identity theft,” said Sen. Debra Bowen, D-Redondo Beach, the law’s author.

Drug and medical device companies must limit the gifts their representatives can give doctors as part of marketing efforts.

“It’s an attempt to woo our doctors and pitch their priciest products, and we’re hopeful this new law clamps down on it,” said Steve Blackledge, legislative director for the nonprofit California Public Interest Research Group, which sought the legislation.

Drug companies can develop their own compliance programs enacting what had been voluntary guidelines proposed by the Pharmaceutical Research and Manufacturers of America trade organization, but must post their programs on their public Web sites.