Something for the weekend: The colder months of the year are usually rife with illnesses, often taking many of us down with them. In fact, the first Monday in February is known as National Sickie Day, the day on which the most people supposedly call in sick.
However, data from BrightHR has highlighted that National Sickie Day was actually ranked fourth highest for absences in 2025.
The HR and absence management software provider analysed its 2025 absence data from more than 1.2 million employees from 120,000 UK organisations.
It found that sickness absences soared by 182% on Monday 6 January, which was the sickest day of the year. Furthermore, the top 10 days for sickness absence in 2025 were all Mondays. Garfield isn’t the only one to not be a fan of Mondays, it seems!
If you’ve ever wondered which employees are most likely to call in sick on National Sickie Day, the research found that it is those named Jack, Amy, Mike, Mark and Christopher.
The cities with the highest absence spikes on National Sickie Day were Blackpool (265%), Norwich (236%), Cambridge (223%), Aberdeen (216%), and Leicester (204%).
Meanwhile, Generation Z is the most likely age group to call in sick, with an average of four out of five employees taking sickness absence at some point in 2025.
Alan Price, chief executive officer at BrightHR, said: “Mondays in winter are still officially the worst for absences, whether due to cold and flu viruses, seasonal pressures on mental health or employees getting creative with why they need a day off. By using employment trends and data to inform workforce planning, employers can make a significant difference to productivity and support. Approaching wellbeing from an employee perspective means emphasising the importance of mental health to encourage a culture of openness and support. This way, employers can increase attendance statistics, productivity and staff retention.
“It’s also key to note the financial impact that sickness absence can have on businesses. Whether employers have already weathered the storm of sickness or are still battling through winter absences, understanding trends in absence data can help them with workforce planning into 2026.”
Maybe employees should choose a day other than Monday to be ill this year to avoid suspicion!
