New tyres come with a releasing agent on them. This is used to allow easier removal of the tyre from the mould during production.
The tyre will 'sweat' off this slippery covering during it's first few heat cycles, as it warms and cools during normal use. It will also lose some (but much less) due to abrasion. Some folk try to 'sand' off the releasing agent with a wire brush or similar, but without heat cycles, this isn't effective.
So you should find your tyres will improve over the next few days. Also, the softer compound in cold weather tyres allows the tread blocks to exhibit greater movement, which causes a feeling of floating, or vague steering feel, particularly with coming from semi worn summer rubber.