"On Saturday and Sunday it is the weekend."
Translation:På lørdag og søndag er det helg.
I know you posted this a long time ago but when you say something like "In the summer, I swim." Norsk: "Om sommeren, svømmer jeg." The verb comes right after the time specified that you swim followed by the subject doing the action. The same goes for this case: "På lørdag og søndag, er det helg." The verb 'er' is said right after the time specified that it is the weekend. Now as for why 'the weekend' is not 'helgen', it is because we are not talking about a specific weekend, we are just talking about the concept of the weekend. Due to the time gap between the time you posted your comment and this one, you might have already figured this out, but I'm still happy to help whenever I can! Ps: If I got any spelling or anything wrong, I apologize.
Excellent question. In the sentence above, "er det helg," means, "it is the weekend."
"Det" is used here as a dummy subject in the same way, "it" is used as a dummy subject in the sentence, "It's snowing." If you flip the sentence around, it might be easier to see: "It is the weekend on Saturday and Sunday."
In Norwegian, det/dette are used—by default—as dummy subjects unless the "real" subject has already been introduced and it's feminine or masculine.
Here's a flowchart that might help:
Indeed "the weekend" is "helgen", but a strictly literal translation is not always correct (as fveldig noted before). The bottom line is that Norwegians would not say "helgen" here, they would say "helg". That's just how the language is. You could flip this argument to English: Note that we don't say "In July and August it is the summer". We would say "In July and August it is summer". So why do we English-speakers say "the weekend" but not "the summer"? No good reason. That's just what we do.