Put them outside when you sow them. Neither snow nor dropping temps will hurt the seeds.

Or, did you mean that you have seeds that already germinated inside and you want to put them out? I've done that before, snuggled up in their containers, but not with anything that is very frost sensitive (like zinnias, for instance). Had no trouble with them.

PV

when you start them inside you have to harden them off and move them out into the garden gradually, getting them accustomed to weather conditions and such. i am a newbie to wintersowing, but i know people are still putting containers out. in our zone tender annuals don't go out for a few weeks, and hardy perennials could have been put out for months. what kind of seeds? i think that would help get a more precise answer for your needs.

i put containers out in 8 inches of snow during a snowstorm-- just dug out a place for them. i would worry more about wind. is there a place you can put them where they will be protected?