Google announced Monday it will offer its personal assistant app Google Now to users of Apple devices, stepping up its challenge to its rival s Siri program.

"Google Now is about giving you just the right information at just the right time," Google s Andrea Huey said in a blog announcement.

"It can show you the day s weather as you get dressed in the morning, or alert you that there s heavy traffic between you and your butterfly-inducing date -- so you d better leave now!

"It can also share news updates on a story you ve been following, remind you to leave for the airport so you can make your flight and much more."

Google Now, which like Siri is a voice-activated software program -- will be available to users of Apple iPhones and iPads, which use the iOS operating system.

"Today, with the launch of Google Now on iPhone and iPad, your smartphone will become even smarter," Huey said.

The move comes with the two California tech giants in a fierce battle for domination of mobile operating platforms. Google s Android has taken the lead in smartphones and is gaining rapidly in the tablet market.

Google meanwhile has argued that Apple s Siri is a potential threat to its core search engine by allowing smartphone users to bypass Google for many searches, which can generate ad revenue.

Google Now s invasion of Siri s turf marks Google Inc. s latest attempt to lure iPhone and iPad users away from a service that Apple built into its own devices.

Google quickly won over millions of iPhone users in December when it released a mapping application to replace the navigation system that Apple dumped when it redesigned iOS last fall. Apple s maps application proved to be far inferior to Google s ousted service.

The app s bugs and glitches made Apple the butt of jokes and fueled demand for Google to develop a new option.
Apple has been losing to Google on other fronts in a rapidly growing mobile computing market, an arena that was revolutionized with the iPhone s release in 2007.

Smartphones and tablet computers running Google s free Android software have been steadily expanding their market share in recent years, partly because they tend to be less expensive than the iPhone and iPad. At the end of 2012, Android devices held about 69 percent of the smartphone market while iOS held about 19 percent, according to the research firm IDC.