Although it was 20°F when I looked at the temperature this morning, the sun and blue skies made me really want to get planting. The real key for whether that is a good idea or not, is the soil temperature. Plant too soon, and the seed may rot before it germinates. Plus, under cold temperatures, the germination will be slow.
I pulled out our soil thermometer and measured at 2 inches into the soil that the sandy plot I have planned for oats is at 49°F which meets the minimum of 43°F. The minimum air temperature for the next 10 days is going in the right direction... plenty of days greater than 60°F. It's time to begin!
I have updated a page about soil temperature here for more varieties.