About the same time that most folks are thinking of heading to the beach or to the mountains for their summer vacations, the American Red Cross begins worrying about how it will provide the blood needed for those who have accidents along the way.

Each year, Memorial Day marks the beginning of an annual and seasonal decline in blood and platelet donations, according to Red Cross officials. With two of the organization’s largest donor groups — high school and college students — out of school for the summer, the Red Cross struggles each year with a drop in its stock of blood and blood products. Students account for up to 20 percent of the Red Cross’ donated blood in a year, so losing those donations makes for a big hole during the summer.

At the same time, summer can bring an increase in the number of traffic accidents and other trauma situations that result in emergency surgery and large transfusions of blood. Red Cross officials say they rely on volunteer donors for the 15,000 blood donations needed every day to support patients at about 2,600 hospitals and transfusion centers nationwide.

With premature babies, trauma patients, cancer sufferers and routine surgery requiring it, America’s need for blood never stops. A trauma patient can need as much as 100 pints, Red Cross spokeswoman Kristen Hatfield said recently, and the average transfusion is about three pints. Every two seconds, someone in the U.S. needs blood, she added.

Suffolk residents can make a big difference during a couple of upcoming blood drives.

The first of those drives takes place Friday from 11 a.m. to 4 p.m. at Mike Duman Auto Sales, 2300 Godwin Blvd. As an added incentive, thanks to Suburban Propane, every donor at Mike Duman Auto Sales on Friday will receive a $10 Visa gift card.

If you can’t make it to Duman’s, there are plenty of other opportunities, like the following: the Suffolk Department of Health and Human Services, 135, Hall Ave., from 9 a.m. to 11:45 a.m. June 29; at the Suffolk location of Kroger Supermarket from 10 a.m. to 12:45 p.m. on July 6 and also at the Walgreens on 3633 Bridge Road from 3:15 to 6:15 p.m. that same day; and at Chesapeake Square Mall at a variety of times on June 27 and 30 and July 1-4.

For more information about dates and times, as well as advice about giving blood, visit www.redcrossblood.org.