How do we know Jesus was 33 when he died?

How do we ascertain the exact age of Jesus Christ at the time of his crucifixion? Is there definitive historical evidence or is it based on biblical accounts and tradition? Given the uncertainty surrounding the timeline of his birth and the varying interpretations of scripture, can we confidently say that he was indeed 33 years old when he passed away? Or is this a widely accepted assumption that may not withstand closer scrutiny?