Due to stricter regulations regarding fire safety, fire retardant treatments of wooden cladding has become more common for low and medium height buildings. Knowledge is available on how to perform these treatments to obtain a sufficient retention for a specified reaction to fire classification, both on modified and unmodified timber. However, little is known about the impact of added fire retardants to the appearance of these surfaces under natural weathering. On the other hand, the extent to which a non-fire retardant treated wooden surface visually changes has been discussed largely in literature. A mock-up was constructed to encompass different exposure levels to test different wood species in 5 combinations. Simultaneously, a test set-up was monitored for the selected wood species without the fire retardants. The appearance was monitored by means of colour measurements and visual observations, during 1 year of outdoor exposure. The findings reveal a spectrum of discolouration effects, including fading and colour shifts. Moreover, significant differences were observed between softwoods and hardwoods. These differences are linked to a difference in fire retardant. Furthermore, the rate and scale of the above described effects are significantly linked to the exposure level. A such, the study highlights how these discoloration patterns contribute to the overall aesthetic evolution of wooden cladding applied to an existing building project in Belgium.