Canadian Blood Services is asking Calgarians to take a few moments to donate blood before wrapping up their summer.

Spokeswoman Judy Jones says nearly 1,200 appointments need to be filled locally before the Labour Day long weekend.

"Right now we'd really encourage O-negative donors to come in. We do like to have five to seven days of O-negative blood on the shelf and right now we're sitting at two to three days," she said.

Judy Jones says nearly 1,200 appointments need to be filled in Calgary before Labour Day. (CBC)

Blood donations usually decrease over the summer, and especially in the days leading up to the return to school for families with children, according to Canadian Blood Services.

Jones says the process at the clinic is all digital, making donating blood more convenient. Appointments can be booked online and the screening questionnaire can be downloaded and filled out at home, she said.