https://www.cnet.com/roadshow/news/tesla-new-supercharger-model-3/

While much of the enabling technology for this comes from the new cable design and a 1 megawatt Supercharger power cabinet, Tesla is updating the Model 3 as well to optimize itself pre-charge. Many Model 3 owners have suffered from inconsistent charging speeds based on the temperature of their batteries. Now, Tesla says, its cars will adjust the temperature of the battery pack as the car approaches the Supercharger to ensure optimal current flow.

However, since Tesla's Fremont, CA Supercharger is the only so-equipped charging station in the US so far, chances are those batteries will already be rolling at pretty moderate temps.