Why was San Francisco's city hall bathed in blue light this weekend? No one seems to know, which I guess means we are free to speculate! (See update below!)

The building's blue glow was first noted by Civic Center's Michael Strickland, who writes that "Though local government spends millions on press spokespersons and elaborate websites for every department, good luck trying to find out any current or useful information from either source."

My efforts were similarly fruitless. No one at 311 knew, referring me to the number for "City Hall Events." A voicemail left there has not been responded to.

Recalling that City Administrator Naomi Kelly was the spokesperson who addressed the extremely minor kerfuffle over City Hall's red and green look during Hanukkah, I tried her office, as well. An extremely pleasant and helpful person there checked with someone else and was told that "the dome defaults to teal." When I said that the blue light was an overall thing, not just the dome default, she said she'd have to look into the matter. I eagerly await her response!

City Hall's typically verbose twitter account has remained silent on the matter, as well.

So let's do some guessing! Was it lit up in honor of autism awareness, as it was in April 2011? Are they promoting yet another Smurfs movie? Was it an early acknowledgement of "Blue Monday"?

Another possibility is that City Hall was aping the city of Chicago, which urged all "downtown buildings to light up blue for King Week, January 11th thru 20th....We want all Chicago to go blue in his honor, and to call us all to be peacemakers," Chicago's Building Owners and Managers Association wrote earlier this month regarding the effort. Could City Hall be (silently, and solitarily) be following in the Windy City's footsteps?

Or, as Strickland writes, perhaps the color in intended to match the likely mood "newly re-elected Mayor Ed Lee, who can't seem to show up for a public event these days without being booed by protesters." Sure, could be that, too! Any ideas, guys?

Update 11:01 a.m.: Literally ONE MINUTE after this report was published, Bill Barnes of the city administrator's office called me. The reason city hall was blue (drumroll...)

"From time to time," Barnes says, "a company will rent out city hall for a private event. The event Saturday was for the company Fitbit, who as part of their contract asked that city hall be blue."

So there you go. Mystery solved, and it only took about two hours and four phone calls!

Related: Why Was City Hall Lit Up With Christmas Colors During Hanukkah?
Mayor Lee Shouted Off Stage By Protesters At MLK Day Event
Day Around The Bay: How Was Your 'Blue Monday'?