Its supposed to run through the 1st, but if you look at tomorrows missions the dark harvest is still there. Thats not how it usually is. When the event is supposed to end the mission will be gone from the preview of tomorrows missions. I guess I could just wait for tomorrow and see, but it would be cool if some GH ppl could clear this up for me (and others) :o
To be fair, the event didn't show up as "tomorrow" before the event started. I would assume at midnight it will simply disappear from the prestige tab.
The event is supposed to run through the 1st, and then end the 2nd. The candies and vendors will stick around until the 8th.
But that's all the official information we have. There isn't exactly the best track record of seasonal events ending on time, for better or worse...