Wintersown jugs don't dry out as long as they stay frozen after being well soaked & drained. But if and when temps rise long enough for them to thaw out, they eventually would dry out indoors unless you water them (soaking from the bottom works well). Outdoors, natural rain and snow do some of that for you.

The trailer would seem to have the advantage of protecting them from strong winds and critters, though.

Don't know enough about your situation to guess which would matter most.

Another thing is that the snow might be insulating your containers from that 15* temp, so that might be another plus for the snow, especially if you're experimenting with something that might be iffy in your zone. (It's hard to be precise about what I mean about "iffy" - so many variables - Trudi explains that so well on her ws site - www.wintersown.org, and the FAQs on this forum go into that very well, too.)

Hopefully others will chime in here.

No the trailer is outdoors. It has no top and so the jugs are exposed to the elements.

Then I don't see why not - seems all right to me to go ahead and keep them in your trailer.

Regarding keeping the milkjugs off the ground - Personally, I try not to keep my ws milkjugs on the ground, because here in Maryland we get frequent thaws, during which slugs are on the move. So mine are up on benches, tables and porch, with sheets of sand paper tied around each bench/table leg to keep slugs off and it works pretty well.

(Another thing I like to do with sand is to put a thin surface of gritty sand on top of my sowing medium - which also retards slug activity as well as keeps small/tiny seeds from sloshing around in heavy rain.)

If you get a really hard downpour when the jugs are thawed and sprouts are tiny, you might want to be ready to throw a tarp over them inside the trailer.

The jugs do need to drain. Is the trailer one with one of those meshy floors? If so, should be fine. If the floor is solid, does water accumulate in it?

Karen

Mary, off the ground is fine. Many, including me, have used their decks, porches, for sown pots in winter. Unless as Karen points out you somehow have a utility trailer that collects water, like a wagon might.