Clinton was to speak today at a Silicon Valley women's conference, her first US speech of the year. It opens a stretch of public appearances in the next month ahead of an all-but-certain launch of her bid for the Democratic nomination.
The former secretary of state has steered clear of the spotlight her only two speeches in 2015 came in Canada last month choosing instead to huddle with advisers as a large field of Republican presidential hopefuls compete for attention.
Clinton is likely to face questions about President Barack Obama's proposal to authorise the use of military force against Islamic State militants, the debate in Congress over immigration and funding for the Department of Homeland Security, and the future of the Keystone XL pipeline.
Also possible: questions about privacy and the US government's collection of phone records and digital communications of millions of people.
Many Clinton supporters say she has little incentive to jump into the campaign now and is better off ceding the spotlight to the Republican presidential field.
The extra time has allowed Clinton to consult widely with economists and begin formulating an agenda aimed at appealing to voters who have struggled with stagnant wages in an otherwise rebounding economy.