Sure you can if you wish but I wouldn't yet. The necks are still green and some of them in the pic look like they could go another couple of weeks depending on the weather. It would't hurt to leave them unless you really need the room for some reason.

Dave

I pulled my over-wintered onions at the beginning of the month (they looked just like yours) because the bed was also planted with veggies I needed to water & I figured they would never brown up if I couldn't keep them dry.

Poor planning on my part, but the onions are storing fine in the garage (I left the tops on). I only had a couple dozen, so they should get used before they rot.

The necks are bent, but I'd like to see the bulbs further up out of the ground. If you harvest them like that, you should use a fork to lift them, or else you'll risk pulling the roots off.

I pulled mine today because I wanted the space for fall peas.

As long as top is green, it means that the plant is alive and well and the bulb can benefit from it.. Water it and wait until the top dies or gets yellow.

thanks everyone! I have no reason to pull them yet; Id like them to grow as long as they can. So I should jut continue watering as usual until the tops start to turn brown? Are you supposed to stop watetring them for a period of time before harvesting?

Yes. I generally stop watering when half the necks have flopped.

Depends on how you are watering. They need normal amounts of deep but not frequent watering, not shallow frequent watering.

I continue to water mine normally until time to harvest them.

Dave

I've found that if you keep watering them after they fall you risk splitting, which is when the onion swells quickly and splits a few layers of skin. While this isn't the end of the world, it does mean the onion won't keep as well.
If there is some ground moisture that should be fine to keep them growing larger till they are done, which should be in just over a week. If it's bone dry, by all means give them a little water.

I see no reason to leave them in the ground till the tops are brown, by that point sunburn becomes an issue. I lift mine while mostly green but dry, brown skin has formed. Then I cure them with tops on in a well ventilated, dry, shady place.

But this is just the advice from someone that grows thousands of pounds of onions every year :)
-Mark