San Luis Obispo Mayor Heidi Harmon will be stepping down as mayor next month. She made the announcement yesterday at a press conference in front of City Hall. She’ll be taking a job as a senior public affairs director at the Romero Institute, a law and public policy center in Santa Cruz. Her last day will be September 26th. The City Council will decide whether to hold a special election or appoint a replacement at a meeting on September 7th.