The less water this time of the year for any palm in cold climates, the better! They dont like too much moisture because that would allow them to freeze. The new growth is also a little bit more tender so all of that growth should be stopping. I plan on covering mine from rain soon and I only cover from cold when its below 25F outside at night or below 40F during the day or both.

Good luck!
-Alex

I guess it depends what kind of protection you are providing them. I am covering mine up this weekend. Our daytime highs have been in the 40s and 50s and nighttime lows in the 30s, so they won't do much growth with those kinds of temps anyway. However, I am covering them with mini greenhouse type structures, so things get warmer during the day under the plastic covering, so I water probably once a month while they are covered up just so they don't dessicate. They do need some water if they're kept warmer. I have a thermostat that turns the rope lights on at 40 degrees, so they don't really see cold temps after I cover them up. It works so well I'm thinking about trying Washys with this protection method next year.

Try putting a remote sensor near the spear so you can see how warm it
is inside the enclosure,if you haven't already.

I cover trachys in my garden only during severe cold. They're fine into the low teens and usually have no problems down to 7 degrees, provided young trunks receive a winter mulch mound in early to mid December. They actually fare worse with season-long wrappings.