Anyone who donates blood through July 21 at a San Diego Blood Bank donor center or mobile blood drive will receive a woven beach towel while supplies last.

Credit: San Diego Blood Bank

The organization said summer is typically one of the most difficult times of the year to maintain an adequate blood supply, even as demand remains steady for patients undergoing surgeries, cancer treatments, organ transplants, trauma care and other medical procedures. Platelet donations are also needed for cancer patients and others with serious medical conditions.