Stanza 1 Summary

Get out the microscope, because we’re going through this poem line-by-line.

The skies they were ashen and sober;

We start out right in the middle of things, staring straight up at the sky.
The speaker is telling us a story about something that once happened to him (notice the past tense). No introductions, no preparation.
Already, though, we can tell that we're in Edgar Allan Poe's world. The skies he sees are "ashen" (gray, pale, the color of ashes) and "sober" (serious, subdued, maybe a little sad). No rainbows, no tweety little birds. In Poe's world, you don't see the sun a lot.

The leaves they were crispèd and sere—

The leaves on the trees aren't looking much better than the skies.
Poe uses a couple of funny words to describe these leaves. The first is "crispèd." In modern language we might just say "crispy," but that sounds more like it's describing Doritos than poetic leaves. "Crispèd" just means that the leaves are crisp, dry, crinkly, and dead. Oh, that little accent above the "e" lets you know to pronounce the word with two syllables: crisp-ed.
The leaves are also "sere," which is a poetic way of saying dry, brown, lifeless. Basically, the landscape we're looking at is pretty grim.

The leaves they were withering and sere;

This is the first of a bunch of near-repetitions that Poe includes in this poem. You'll notice right away that line 2 and line 3 are practically the same. Poe just changed one of the words for the leaves from "crispèd" to "withering."
The two words mean pretty much the same thing, so why change it? Well, repetition is a great way to make something stick in your head, so repeating the bit about the leaves is a way of underlining the image.
It also gives Poe a chance to try out a new sound here. As we'll see, this poem is all about the sounds of words (well, all poems are like that, but this one especially).

It was night in the lonesome October

Now we start to get a little more concrete detail about where we are. Apparently, it's nighttime, and it's October.
What kind of October? How does it feel? Happy October? Sparkly October? Of course not. This is a Poe poem, so this has to be a "lonesome October." (Maybe also a Halloweeny October?)
"Lonesome" is a pretty classic Poe adjective, and it reinforces the dreary feeling he's creating.

Of my most immemorial year;

Our speaker is being a little mysterious here. He won't tell us what year it is, just that it was "immemorial." That's kind of a tricky word to use here. Usually, that word is used to mean that something is "beyond memory," that it started so long ago that you can't remember when. That doesn't make total sense here though, because, as we'll see, the speaker has a good reason to remember this year.
On the other hand, he has a good reason to want to forget it. We think Poe is using this word because it's a little hard to pin down. It can make you think of both memory and forgetting. This poem is all about those two themes, and how they struggle with each other.

It was hard by the dim lake of Auber,

Now we know what the landscape looks like (gray, dreary), the month (October), and time of day (night). We still don't know where we are, though. So the speaker helps us out…sort of.
Apparently we're "hard by" (that just means "right next to") a lake called "Auber." You couldn't find that name on Google Maps; it's not a real place. Still, it helps to create a sort of otherworldly, fairy tale feeling.

In the misty mid region of Weir—

The lake of Auber, it turns out, is in a place called Weir. Actually, it's in mid-Weir, for what it's worth.
We don't think it matters where in Weir we are, or even where Weir is. It's all about the sounds. "Mid" makes a nice sound when it's next to "misty," and we need ten syllables in the line, so it makes sense to throw this little word in there.

It was down by the dank tarn of Auber,

This line is another almost-refrain (a repeated line), like the one we saw in line 3.
The speaker repeats line 6, but changes the descriptive words, and a couple of the details. He calls the lake of Auber a "tarn" this time (that just a fancy word for a small lake) and tells us that it's "dank" (damp and cold), instead of "dim" (line 6).

In the ghoul-haunted woodland of Weir.

Here we repeat line 7, with a few changes, like before. The details are just getting spookier.
We learn that the land we're in is wooded. More importantly, we find out that Weir isn't just "misty," it's also haunted by ghouls (evil spirits that feast on the dead)!
So, to recap what we've learned in the first stanza: It's nighttime in October and the speaker is next to a dark, misty, damp lake in the middle of a forest filled with ghouls. Ah, classic Poe.