In most of the Desert Garden, we're now in the coldest time of the year. Even with the warm and sunny days, the night-time temperatures still dip low and even hit freezing. We're accustomed to paying particular attention to watering the vegetable garden when the temperatures are blazing hot; when the weather is cold, it's easier to forget, but no less important.
Unwatered plants will wilt, dry up and stop growing; more slowly than in the Summer, but the results are still the same. And careful watering is a good frost-management strategy: well-watered plants tend to survive frosts more readily than dry and wilting plants, and moisture evaporating from the soil can provide a slight temperature boost on a cold Winter's night.
Water your vegetables as deeply as you would in the Summer (to a depth of one foot in most cases), just not as frequently. The frequency depends on a number of factors, including the soil condition, use of mulches, humidity, and daytime temperatures, so the only real way to know when to water is to get a finger down there in the soil and see if it's dry.
Many of our Winter vegetables can get a little leggy, especially if they have less than the ideal amount of sunlight, so to avoid knocking them down, always water at the base of the plants rather than overhead.
And don't forget to harvest as your plants mature; if you planted this Autumn, you should have radishes, lettuces, beets, broccoli raab, and endive ready for the table.