It's pretty much freezing everywhere else on the planet ... but this weekend in L.A. it was in the 70s -- and "Shahs of Sunset" star Mercedes "MJ" Javid took full advantage of the warm weather.

Not wanting to waste a moment of sunlight, Javid stepped out in her natural habitat on Sunday -- a hotel pool -- and sunned herself in a wild bikini.

Don't hate us 'cause we're beautiful.