October in Rome is one of the best months! The weather is typically mild and pleasant Average highs: ~70°F (21°C) Average lows: ~55°F (13°C) It can be sunny and warm during the day, with cooler evenings. Light layers are ideal.
Downtown Rome is easily accessible from Fiumicino, just a 20–25 minute ride by car or train.
The Leonardo Express runs from the FCO Airport to Rome City Center every 15 minutes and stops in Trastevere and Piramide/Ostiense - from there you can take a quick trip on a local train to other locations including the Vatican, Colosseo, and Termini.