A pressure-sensitive adhesive (PSA) composition and method of use across a wide operable temperature window. The PSA composition includes a triblock copolymer rubber with relatively low diblock content, an aliphatic tackifier, an aromatic tackifier, and an oil-based plasticizer. The combination of components results in the PSA having a phase-separated morphology, where the PSA includes two domains that do not mix with each other. This morphology’ results in superior performance of the PSA across a wide range of temperatures, such that separate adhesives for low temperatures and high temperatures are no longer required.