In the episode "Once A Thief", Grady put the radio in the freezer to keep it hidden from Lamont's friend (Herman) that just got out of prison.

But when Gray took the radio out of freezer which was covered with ice, he plugged it in and it blow up with flames and smoke coming out of it. That should have been enough to melt the ice. But it didn't.

Then Grady send Herman to store to pick up a pocket radio, and when Herman returned (which must have been about an hour), the damaged radio was still sitting on the table covered with ice on top and sides.

So conclusion is the ice was either fake, or it must been one hell of a cold night in LA :D

https://lh6.googleusercontent.com/proxy/2Gp5WNzbxA7TYgST2Ay8BAKBqzfeGulnPX9mWmpWc4cDxVkZjwa0XRHktvTEHmPFF5evNK8R0pXZDfFZyMDvvtO6lmYjJQnjjVPami-Ek1vgPbk=w1200-h630-p-k-no-nu