I have no experience with Giro/Giant/Bellweather gears, so can't speak specifically to them. Here is what I use for between somewhere between 20-30 degrees:
- a skull cap that covers ears (or a balaclava if it gets closer to 20 degrees)
- a neck gator that can be pulled up to cover part of your faces (no need if wearing a balaclava)
- a windproof jacket: the Castelli Gabba convertible that works wonders
- a long-sleeve baselayer: the Craft thermal baselayer is great, very warm and don't trap moisture
- bib tights that has windproof front: the Castelli Sorpasso Wind can get me through pretty much as low as I ever want to ride including single digits
- shoe covers: I use the Gore ones with the WindStopper material
- wool socks
- windproof insulated gloves: Giro makes a great one for my hand size/shape. I don't remember the model, it's from their city riding range, not the normal racing stuff.