The Zimmerman 911 call is being analyzed like the Zapruder film for evidence that he uttered a racial epithet. It’s one of those things where suggestion is very important—if you know what you’re listening for, you’re more likely to hear it. Blogger Neil Schulman has augmented the audio and thinks Zimmerman clearly says “it’s f****** cold.” Listen for yourself at this post. (Knowing nothing about the technicalities of audio, I can’t vouch for his technique.) You can compare it to the CNN enhanced audio here. I hear “cold” in the Schulman version and something like “coons” in the CNN version, but “it’s” in both versions.
Some commenters are asking what the temperature was. Schulman points out that it may have been chilly for a Floridian.