Modern asphalt shingles are designed to seal as temperatures rise, but they do not need summer heat to begin bonding. While a strong seal forms more quickly on warmer days, shingles installed in winter still adhere properly as long as they are placed correctly, fastened to manufacturer specifications, and exposed to normal sunlight over time.

In the Southeast, daytime winter temperatures often rise enough to activate the shingle seal strips. Roofers also use techniques such as adjusting nail placement and securing edges to ensure the shingles stay stable until the seal forms naturally. A qualified crew knows how to install in cooler conditions without compromising durability.