The St John’s Co-Cathedral Clock, which is found on the south bell tower of the building, has three faces marking the hours, the days of the week and the date of the month respectively. The main one is the clock of the hour, where a Latin inscription shows the name of Clerici, a Maltese clock-maker, who connected the clock mechanisms of three bells. These ones have a high relief coat-of-arms of the Grand Master Wignacourt and the large bell has the date 1619, the date when it was probably cast and the construction of the clock.

The restoration was completed in January 2018 which consisted of cleaning and stabilising the deteriorated surface. The surface was also repaired, loose parts plastered and the inscriptions, the numbers and decorative elements reintegrated. All the deteriorated metal supports were replaced with new ones made in stainless steel, whilst the arms were cleaned and painted with black varnish. The weather vane, which needed extensive restoration, was repaired in the laboratory and reinstalled. Moreover, also the wooden spool on which it spun was replaced because of deterioration and all the moving parts repaired.