Tar can become stiff, hard, or brittle in cold weather, but it usually does not freeze like water. Its low-temperature behaviour depends on composition and additives.
When people ask whether tar freezes, they usually mean whether it becomes unusable in winter. Many tars and tar-like products become much thicker as the temperature drops. A brush may drag, a coating may not level, and a once-sticky material can feel hard or glassy.
This behaviour is not the same as water freezing into ice. Tar is a complex mixture rather than a simple liquid with one neat freezing point. Different fractions within the material can stiffen, crystallise, or remain mobile at different temperatures. Additives and solvents can change the behaviour again.
Traditional wood tars, including Stockholm tar, may need warmth for easier application, but heating tar casually can create fire and fume risks. Modern products should be used within their stated temperature range rather than forced into winter work.
Cold weather also affects the surface being treated. Damp, icy, or frozen wood can prevent good penetration and leave a poor finish. The better question is not just whether tar freezes, but whether the tar and the surface are warm, dry, and suitable enough for the job.