Shingles installed in cold climates may not be sealed immediately until there are warmer temperatures for the sealant to activate. Temperatures are at or below 40°F (5°C). While installing shingles in winter is possible with preparatory work and the right materials, it requires a little more attention. If winter installation is unavoidable, most asphalt tile manufacturers require a specialized adhesive to be manually applied to each tile for temperatures below 40°F (4°C).
If the tiles are applied below 40° without specialized adhesive, you run the risk of voiding the warranty. The temperature too cold for roofing is 30 degrees Fahrenheit. Most roofing companies will tell you that they don't install ceilings below 40 degrees. This is because asphalt shingles tend to crack below that temperature.
In colder temperatures, the shingle material becomes less flexible, making it more difficult to bend and cut. This makes it especially difficult to install tiles using the shelving method, which requires lifting or bending them to place the last nail. This is especially problematic with shingles placed in the valleys, hips and ridges, as these areas require the highest degree of manipulation of the tiles. If shingles become brittle, you also run the risk of nails breaking or overloading them if the roofer doesn't know the best practices for pressure calibration.
Roofing companies are used to installing roofs during the winter months, especially in colder climates, where temperatures tend to drop below freezing. In addition to the physical precautions of cleaning work surfaces and wearing appropriate clothing, there are some additional steps roofing companies must take to properly and safely install roofs in very cold temperatures. Shelving is a roof installation method in which tiles are installed directly on the roof instead of being installed using the traditional step method. Speaking of roofing materials, remember that shingles won't be as flexible at colder temperatures, so you should avoid placing them in places where the beams bend or deform or maintain that shape while you try to install them (for example, on roof peaks).
Try to keep them as flat as possible until just before you need them.