One of the first things I learned about the Harrisonburg area when I moved here in 2004 was that early Spring planting will likely turn out to be a waste of time and money. It is very important to wait for the last frost before planting your new Spring plants. With weather like today, though, it is tough to be patient! As soon as the sun comes out and temperature reaches 70 degrees, most people like to get out and get busy in the garden. The best advice I can give you is this: WAIT!
Here is a map of Hardiness Zones in the United States. Harrisonburg is in zone 6, so the last frost will likely not show its ugly head until late April or early May. To get a better idea of first and last frost dates in our area, click here to see a nice tool provided by Lowes.
I couldn’t agree more. One year, I did exactly what you talked about – I got all excited about warm weather at the start of May and I planted squash, tomatoes and peppers. Sure enough, that very weekend we had a cold snap and frost took almost everything. Grrrrr! I would actually suggest waiting even longer than you suggested – perhaps until the second or third week in May – just to be safe.