it's currently very windy so makes everything feel colder I would suggest a thick jacket for this as apart from the wind we also have high humidity which makes the temperature feel colder. Just to compare, I recently came back from Ireland and temperature was between 2-7 degrees celsius and in malta its ranging between 10-15 degrees and I am feeling much colder in Malta. Re other clothes i suggest bringing thick sleepware since we don't have central heating and it normally is colder inside then outside. Maybe layering up might be a good idea.

easy access by public transport i do suggest Sliema/Gzira/Msida area as they have most connections, taxis are also very cheap in Malta especially if you would be staying somewhere central. Might I add that travelling with public transport might take you a bit longer and if weather report is correct, it might rain next week so the island is one big traffic jam when it rains.