Last summer was the most recent completed summer. For your poll, it was earlier this year (2017).
This makes sense to me in the same way that last week, last month, last year, last meal, last time all mean the most recent completed week, month, year, meal, time.
Of course, for us Southern Hemisphere folk, this gets a little more confusing, since our summer is both ongoing and spans two calendar years. In that case, since the current summer (2017-2018) is ongoing, last summer was one year ago (2016-2017).
But the seasons seem more like the days of the week in speaking than the months of the year in my view and I would not say “Last Wednesday” on a Friday if I meant the Wednesday that just passed two days ago. Just like the days of the current week get special consideration, the seasons of the current year also do too. Winter being the exception since it bridges the year and is kind of the starting point and end point. “Last Winter” would definitely mean the Winter of 2016-17.
I don’t think “Last night” or “Last year” are good analogies because those are essentially compound words that have a specific meaning whereas “Last Summer” or “Last Wednesday” is more like a math equation.
And I think I’ve spent way to much time thinking about this now
This must clearly be a feature of dialect. Talking about summer 2017, I would say “What did you do this summer” or “what did you do this past summer.” Like I said above, where I’m at, “last summer” implies “last [year] summer.”
Now, when it gets a little ambiguous, I will disambiguate. For example, you people who use “last” and “next” to mean the next day/month/season in sequence, if it’s Tuesday, is “next Wednesday” tomorrow? That would sound extremely weird to me. Same in the other direction. If it’s Friday and you ask me about “last Wednesday,” it would never occur to me that you’re talking about the day two days past.
Now, if it’s Sunday, and I say “next Friday,” since it’s far enough away, I will probably disambiguate it by saying “let’s meet next Friday, not this upcoming Friday, but the one a week after.” Or “let’s meet a Friday a week from this Friday.”
But, with a full quarter of the people reporting this sort of usage, this suggests to me that it’s dialectal (or that Dopers are unusually pedantic and mathematical in picking the first option.)
Here’s a similar thread about the use of “next Wednesday” when the current day is a Monday. The rules that apply for that sort usage apply (for me) for the usage for temporal phrases like in the OP. I notice that the people I know are from my area use “next Wednesday” not to refer to the literal next Wednesday, but the one nine days from Monday.
One problem with basing it on the calendar year is that, for many people (especially those who are in school themselves or have kids in school), it’s at least as natural to think of a year beginning in the fall.
I’m with the majority on the OP’s question, but perhaps the minority here. Last November was in 2016, but last October was 2017. It’s only December right now, and I think you have to get out of an adjacent period before you start calling something “last” anything. Technically, yes, last November was Nov17, but consider if you were not scheduling an international business meeting, but instead, fighting with your spouse:
“That’s what you said last November!!”
There’s no way the spouse means you said something 30-ish days ago. They mean roughly 13 months ago.
You have to give it space before a time period becomes “last.” The holiday that happened a month ago is still “this Thanksgiving.”
