NHS Greater Glasgow has apologised for the fiasco last Wednesday.
One angry Bishopbriggs man told the Herald how his mum, who is almost 80 years old, ended up having to leave without receiving her vaccinations.
Paul Duncan said: "We got there just after 3pm and the line was away round Kirkintilloch Town Hall building. We finally got on to Union Street around 3.35pm so could see the doors to the building.
“Then the heavy rain started. Staff stopped letting people in. It was a disgrace. My mum is nearly 80 years old. The water was pouring from both of us so she just had to leave.
"She was in tears. A lot of the old folk were upset. The NHS simply don’t care about older folk any more.”
He added: “I phoned up NHS and a guy on phone was trying to make me out to be stupid, saying ‘are you sure you were at the right place and date!’ My mum had the letter with her.”
Paul said there dozens of people still waiting in the rain when they left.
He added: “I have logged a complaint with the NHS as no way old people should be made stand outside like this. So many also had the same time appointment time as I asked a few people. Why do this?"
A spokesperson for NHS Greater Glasgow said: “We are sorry people had to wait longer that they would have expected when they arrived for their vaccination appointment at Kirkintilloch Town Hall.
"We will contact the patient directly and will provide any support that is needed.
Vaccinators have been working incredibly hard over the last 12 months and we are thankful for their continued commitment to ensuring those receiving their vaccinations, are processed both swiftly and safely.
“Unfortunately a scheduling error has led to our clinics being overbooked particularly at lunch time.
"We are working closely with the national scheduling team to ensure the issue is resolved so as to limit future disruption.
“If any patients are concerned about accessing a clinic, we would encourage them to call the national helpline on 0800 030 8013.”
People with mobility issues who need to attend a vaccination centre can use SPT's bookable, door-to-door MyBus service. Registration is required prior to booking and advance booking is recommended, as capacity is limited due to social distancing requirements. Details are available at spt.co.uk/bus/mybus or tel: 0345 128 4025.