This is another example of the kind of "tricky" sentences I hear people complain about. Literally read, it looks as if the sentence is asking "Was last year summer?" or something nonsensical like that. I, for one, didn't quite make the immediate connection between van meaning "there is" becoming volt meaning "there was". (Plus the sentence itself not making any sense also helped; there was obviously a summer last year, so it seems like the sentence must be asking something else.)
Well, Hungarians are full of tricks. :) This sentence is actually asking whether there was a summer last year. This typically refers to the weather. Was the weather summer-like. Hungary is a country with four distinct seasons. And sometimes the summer is full of rain and not-so-nice weather. So you could say something like "We didn't have a real summer this year".
I live in Canada and can fully understand the meaning of that question. I nevertheless agree with Arcaeca. This whole section should be revised. There are too many cases where a perfectly correct answer is rejected and some questions questionable.
I understood what the sentence meant. One could say to someone if the weather had been bad, "Did we even have a summer last year?" meaning we skipped summer because the weather was so bad.
While the question may be valid between friends asking whether there was a season worthy of being called summer last year, it isn't something I'd have guessed seeing this question for the first time.