Translation:It may rain on the weekend.
I don't believe even all US Americans say 'It might rain on the weekend.' In British and other Englishes 'on' is only for single days and it is only correct to say AT the weekend. If they are not going to accept the above rule they should at least accept both answers!!!!* ^ >:(
Feed up having to translate into American English - ie on the weekend - British English is at the weekend. Could both be accepted please? This happens in multiple languages in Duolingo. On relates to a specific day - ie on Saturday. At relates to a period ie at night, at the weekend. BBC World Service states: We use at when we are discussing precise times, weekends and public holidays:
What time does your train get in? ~ It gets in at five twenty five. Let's meet at Waterloo Station at the end of platform one at five thirty. What are you doing at the weekend? ~ I'm going to see my parents at Easter, but I've got no plans for next weekend.
I think sometimes people get worried when their answers are perfectly acceptable but Duo marks it wrong. It's easy to see when the acceptable answer is in your own native language. But remember, Duo doesn't have all the possible answers in its tree. Just because your Mando got marked unacceptable doesn't mean it's wrong
With that said, in these types of sentences the 会 can be optional because the time words indicate it will happen in the future
In this pattern, the 会 can be removed and the sentence understood
Apparently 'might' is accepted in some phrasings of the sentence. My translation 'it might rain at weekend' was rejected and corrected to 'it might rain the weekend'. Obviously, the 'the weekend' is plain nonsense here. 'At weekend' is a perfectly correct translation, I have been reporting it in different sentences for months, but nothing changes. 'On the weekend' souds very awkward to me, but seems that somewhere it is used.
I opened a question on the topic over on Quora. Only two answers so far and nobody yet knows "at weekend" but more answers should come in.