There's actually nothing strange about this. If you look around your garden, many plants are sowing their seeds now themselves.
Many perennial and cool-season annual seeds do best when they are planted now. Many perennial seeds benefit from the exposure to cold weather. The repeated freeze-and-thaw cycle actually aids in germination; it's called vernalization.
Many cool season annuals also do best if sown in fall. Nearly immune to winter cold, they actually grow and thrive during winter and are much stronger than if planted in spring. These "polar" plants include old-fashioned favorites such as larkspur, California and corn poppies, bachelor buttons, love-in-a-mist, pansies and silver dollar plant.
Most of these can just be sprinkled on the soil and pressed in firmly. It's advantageous to time this just before a rain or snow event.
On those cold days inside, turn your attention to potting rooted cuttings. If you took cuttings this fall from tender plants such as geraniums, coleus or bloodleaf, they may be ready to pot. I root cuttings in water in glass jars on the windowsill. When they've grown lots of healthy roots, they can easily be planted in soil and nurtured on the windowsill.
Cuttings of succulents and African violets can also be rooted easily. Skip the step of rooting them in water and simply insert their stems into soil. If space is at a premium, they can be grouped together fairly closely in a shallow tray of potting soil. After they root (a gentle tug will indicate they have), the new plants can be potted up individually.
By taking advantage of our "down time," gardeners can keep active and get a small jump on spring.