I'm at roughly 1/2 litre per tap for the season too (about an hour's syrup for Ennis! ) Didn't collect sap yesterday after the scout came back reporting 6" of water on the trails, and 1/4" sap in the buckets. Boiled off remaining Monday sap though and all the tanks are empty. Will likely collect whatever there is tonight but not expecting anything spectacular.
As Yellzee indicated, the radio forecast is calling for more freezing nights but the web forecast isn't. I'd like to have sap to boil this weekend, one son is coming home from Uni between exams and he enjoys collecting and boiling as much as the others. He missed out his last visit due to the late start.
We have lots of snow in the bush still, although my trails are now mud (where they aren't water). Snow is disappearing quickly anywhere it's exposed to the sun. A few more cold nights would be good.

