You may have spring fever from the recent balmy conditions, which may inspire you to plant your spring garden. Don't do it yet, though.
Hold off on those plans -- or have a way to protect your plants through the rest of the season.
Average Last Spring Freeze
Temperatures will remain variable over the next few weeks, and a killing frost/freeze is not out of the question.
Keep in mind that cold-sensitive plants, like tomatoes, do not do well even if the air temperature is above 32 degrees (gardenguides.com says that tomato plants can get injured when temperatures are in the low 40s). Even in sheltered areas, like covered porches, chilly temperatures can harm sensitive plants. Be sure to have a way of bringing them inside, or develop a way to protect them if they are already established in the soil.
The "usual" rule of thumb is to wait until after Easter to put your sensitive plants in the ground -- but sometimes, Easter arrives early, much earlier than the average final frost for the region.
So if you haven't started your spring garden yet, try to hold off until mid-to-late April. A good rule of thumb is to wait until after Tax Day (April 15). Some say you should wait until May 1 to be safe.
It's okay to plant cool season crops now, such as collards, lettuces, onions and kale.