Hi, sujiwan - Victory Seeds has a listing of frost dates for other cities in MD - perhaps Hagerstown's dates would be appropriate for you (they're Zone 6, too).

Here is a link that might be useful: Victory Seeds frost date listing

Greetings from Westminster! I live near McDaniel College. I have seen published last frost dates anywhere between April 15 and May 15. I tend to be pretty conservative on my planting out dates, so I go with May 15. I figure if I put all that work into the seedlings, I'm sure not going to let them freeze to death!

Based on watching the blooming plants in Baltimore City, I'd say we are a good 2 to 3 weeks behind the downtown business district.

On weather.com, put in your zip code, then select "Month" and move forward to April. It will tell you the historical averages, mins, and maxes, for the dates not within a 20-day present spread.

On April 1, you can move to historicals for May.

This is as good or better for me that official frost dates, because I can decide how risky I want to be.