You'll have to watch it for when it begins to put out new offsets. For me, the whole "summer/winter" growing thing just doesn't tend to work quite that way. In my climate at least there are several periods throughout the year when they grow and then periods where they don't. I only water haworthia when they get squishy anyway.

Haworthia will go to sleep if it is too hot (at night) or too cold (during the day). The calendar month doesn't matter. On a windowsill indoors they can grow all year if given enough good light.

Since winter light is usually poor, it is best to keep watering low and try to keep the plant from "wanting" to grow. In the summer if the nights are warm (no air-conditioning) the plant will go into a semi-dormant period as well where watering should be reduced.

The best thing to do is observe your plants and take their cues. An actively growing Haworthia will have bright new leaves at the center of the rosette, and will respond to more watering at this time.

Ok, that is good to know, thank you both. The pup that I potted up separately has brightened up considerably and the leaves are plumper since I watered them. The coarctata also looks cheered up. The big attenuata isn't looking any better and I'm wondering if it's time for a repot, the one it's in is a bit small. I'll just keep an eye on them and remember to back down the watering when the nights get hot. They're still inside, but will be moving out to the balcony in a few weeks I think.