Please be aware that Brussels and Rome has multiple airports and that these results are for all airports serving the city.
The best month to fly between Brussels and Rome is September and the most expensive month to fly is April. (Average prices, based on 212 datapoints.)
The best day to arrive at Brussels is Tuesday and it would be best to avoid Friday, as prices are on average 148.64% higher than on Tuesday. (Average prices, based on 220 datapoints.)