While blackberries grow and ripen from late spring to early fall, peak season in the United States runs from July to August -- with the harvest beginning earlier in Southern states and later in the Northwest.
http://www.livestrong.com/article/482462-when-are-blackberries-in-season/
1 Obviously, the thornless are easier to pick, but some people claim the thorny varieties are sweeter. With the thorny plants, you want to reach into the plant in the gaps, so you don't need to touch anything but the berry you're after, avoiding the thorns.  A ripe blackberry is deep black with a plump, full feel.
http://www.pickyourown.org/blackberries.htm
Berries in Season. Blackberries, which are native to North America and parts of Eurasia, mostly grew wild until cultivation began in the late 1800s. The U.S. Pacific Northwest and the European country of Serbia lead the world’s production of blackberries, with Oregon being the top-producing U.S. state.
http://www.livestrong.com/article/482462-when-are-blackberries-in-season/
What's in season in August 2016, and other timely information: Notes for August 2016:Blueberries and blackberries are ready NOW in most areas; as are peaches, raspberries. tomatoes and corn: See your state's crop availability calendar for more specific dates of upcoming crops.
http://www.pickyourown.org/blackberries.htm
In order to produce good local Blackberries, producers depend on ideal spring and early summer weather conditions. See this page for a list of blackberry festivals around the U.S. Blackberry Facts and Tips. Black Raspberries, also known as black caps are a very healthy food; packed with anthocyanins!
http://www.pickyourown.org/blackberries.htm
Portland Farmers Market (Photo credit: Allison Jones) If you’ve been eagerly awaiting Oregon berry season, you aren’t alone. Portland’s Ken Forkish (owner of Ken’s Artisan Bakery and three-time semi-finalist for the James Beard Award for Outstanding Pastry Chef) fully embraces the bounty of Oregon berries each summer. “The joy is in the variety that we have. Once summer kicks in, it is a different berry every week,” he says. With local berries ripening throughout the season, you can enjoy a summer of fruit. Look for strawberries from early May through June and then again in August through September.
http://traveloregon.com/trip-ideas/oregon-stories/berry-season/
When you think of blueberry season, you might imagine long, hot summer days, iced tea and lemonade. Growing up, you probably only ate blueberries as a summertime fruit, but we’ve got news – these wonderful little berries can add flavor to any dish (or be served as a simple snack) at any time of year! Thanks to our friends in South America, we have them at our finger tips year-round.
http://www.blueberrycouncil.org/about-blueberries/blueberry-season/
The domestic blueberry season runs from April to late September, and once that wraps up, imports from Chile and Argentina start flowing in. In other words, fresh blueberries are always available; from October to March, you can find juicy and plump blueberries in the supermarket just like you do all summer. That said, there are other ways to take advantage of peak blueberry season here in North America (June and July). Since other forms, like frozen, are just as yummy and easy to use, you can stock up the ample supply of fresh blueberries in the summer time, and keep them in your freezer for up to six months.
http://www.blueberrycouncil.org/about-blueberries/blueberry-season/
By Monica Kim on June 20, 2014. Share. With the hot, sticky summer months comes one of life’s greatest joys: Fresh berries, easily found in farmer’s markets across the country. In your haste to enjoy the season, however, you may not have noticed that the quality of your fruit can vary wildly from batch to batch.
http://modernfarmer.com/2014/06/find-seasons-best-berries/
How to Find the Season’s Best Berries. With the hot, sticky summer months comes one of life’s greatest joys: Fresh berries, easily found in farmer’s markets across the country. In your haste to enjoy the season, however, you may not have noticed that the quality of your fruit can vary wildly from batch to batch. Sadly, the secret to finding consistently delicious berries is not as simple as buying local or organic. In 1983, Jim Cochran and Mark Matze founded Swanton Berry Farm on four acres of rented land in central California. Although Matze left after a few years, Cochran soldiered on with his crop of organic strawberries.
http://modernfarmer.com/2014/06/find-seasons-best-berries/
when is berry season?
Berry season is from early May through June and then again in August through September. Berry season is in early May through June and then again in August through September.