When all aloud the wind doth blow, And coughing drowns the parson's saw,
At first glance, it looks like the second stanza is going to proceed much like the first, with a whole bunch of "whens," followed by a "then." Cool—we guess.
This time, the speaker says that, when the "wind doth [does] blow" really loudly ("all aloud") or audibly, and when "coughing drowns the parson's saw" then… well, yeah, we don't know yet.
In this particular instance, a "saw" does not refer to a cutting device that you would use on those "logs" we met in the first stanza. Here a "saw" means something like a sermon, delivered by a parson (basically, a pastor or minister). So, when this guy is trying to preach, the cold and sick members of his congregation cough and interrupt.
Ah, winter: always ruining everything. Well, that's what it seems like at least. If these folks are sick, why don't they stay home anyway?
Just a thought.
And birds sit brooding in the snow, And Marian's nose looks red and raw; When roasted crabs hiss in the bowl,
As we expect at this point, we get some more anaphora to tell us that we're still dealing with a giant "when x, then y" structure.
Anyway, the sequence continues by saying when birds sit in the snow, and Marian's nose gets irritated, and when the crabs are good and roasted, then… ugh, we still don't know (yet).
Before we find out, there's a lot to cover in these lines. First up, the birds are "brooding," which can mean anything from "to lay and hatch eggs" to protecting eggs to just hanging out, sitting down. It's the winter, so these birds probably aren't protecting any eggs. More likely, they're just chilling (get it?).
Now, for those "roasted crabs." At first, you may think it refers to actual crabs—you know, from the ocean, the guys on this show.
Our sources have told us, however, that this is not the case. "Crabs" here refers to crab apples—a very sour, and much smaller, species of apple.
The "bowl" mentioned here is a bowl of ale, so roasted crab apples are put in a bowl of ale, probably to give the ale a sweeter flavor, or to make the ale a little more festive.
The "crabs" probably "hiss" because they are tossed into the ale while they're still piping hot from the oven, which makes that hissing sound.
We know, apples in ale? Sounds crazy doesn't it? It's not. There are actually a bunch of recipes involving ale or beer and crab apples, it turns out. Enjoy (but only if you're 21 or older).
Then nightly sings the staring owl, "Tu-whit, to-who!"— A merry note, While greasy Joan doth keel the pot.
Well, it turns out that exactly the same thing happens in the second stanza as happened in the first; when Marian's nose is red and people are coughing and the apples are hissing, that same "staring owl" hops on the mic and sings every night.
He sings the exact same song, or "merry note," that he sang in the first stanza: "Tu-whit, to-who!" While he sings, "greasy Joan doth keel the pot," meaning she stirs the pot of stew or soup or whatever in order to cool it off just a bit.
As we mentioned before, "greasy Joan" is probably just a generic name, the "greasy" part signifying her role as a cook or chef (they have a tendency to get greasy).
As with the first stanza, this one has a rhyme scheme of ABABCCDEF, for the most part.
And by "most part," we mean: Did you notice how similar "note" and "pot" look? Oh yeah, they both end with a T and they have an O in them. These words don't really rhyme at all, though, so this is an example of an eye rhyme, or slant rhyme, or half-rhyme, or "any word that's like half or slant rhyme." In other words, the T sound sort of rhymes, but the words themselves aren't similar enough to make this a "true" rhyme that we can signify in our little scheme.
So, there you have it folks: a Shakespeare poem about how winter freezes everything (blood and milk and noses) and messes things up, but still somehow permits life (the birds, the owl, the pot of stew, the fire, and the folks who get to slurp down some sour apple beer—yum?).