Based on what I see here, a jacket and an umbrella would help you enjoying your stay in Rome!
Second column is high/low temperature expressed in Farenheits degrees. Third one is a general description of the weather. Fourth column shows how likely you are to get some rain during the day. Please note that it doesn't mean that it will rain 80% of the day when it is written 80%. It just mean that when you have those weather conditions, 8 out of 10 times, there was at least few minutes of rain during the day.
Fifth column shows the wind direction and speed. Doesn't look too windy there.
Last one is the humidity percentage. When it is quite humid, it reinforces the feeling to have a cold or a hot weather depending on the temperature, especially with low wind.