Ambient kitchen temperature affects knife performance primarily by influencing the food's texture. Warmer temperatures can soften food, making it more difficult to achieve clean, precise cuts.
The ambient temperature of your kitchen directly impacts the temperature of the food you're slicing. For example, if you're slicing butter or cheese, a warmer kitchen will cause these items to soften. Softer foods tend to smear or compress under the knife's blade instead of yielding a clean cut. This is because the blade encounters less resistance in a softened state, leading to a less controlled slicing experience. Conversely, colder temperatures can make some foods, like meat, firmer and easier to slice thinly. The ideal slicing temperature depends on the specific food item. For instance, sushi chefs often work in cooler environments to maintain the firmness of the fish. The type of knife also plays a role; a very sharp knife can mitigate some of the effects of temperature, but even the sharpest knife will struggle with overly soft or sticky foods.
If you're struggling to slice a particular food cleanly, try chilling it in the refrigerator for a short period before slicing. This can firm up the food and make it easier to cut, especially in a warm kitchen.