Dutch iris are bulbs that bloom once in the spring.

If you mean reblooming bearded iris, you can divide now with some warnings. If you are in a cold winter climate they won't have time to form a new root mass before freezing temps. Bad idea for those places even if a warm spell has hit.

If you're in a zone with no significant winter freeze you need not worry about that. Often beardeds skip blooming the year after dividing.

If you want the cut stem's buds to open, they need to be showing some color before cutting.

Ack! I meant bearded iris, not Dutch. (I also grow some Dutch Iris and I know they bloom for about 2 weeks in Spring only).

I live in southern CA in a zone without significant freeze --- temps down to mid-20s are not unheard of but more typical are low 30s. It sounds like it is safe to dig, divide, and move them now while I have the opportunity.

Thank you for the tip about cutting the stem; I didn't know that.

Good luck.