Standard asphalt shingles feature an adhesive strip that softens during warm weather, especially when the sun’s rays hit the roof directly. When the shingles heat up, they become flexible and the adhesive bonds the shingles in place. Before new shingles seal down, they can look a little lumpy and uneven, but once the roof gets hot enough, they should soften, flatten and form a permanent seal. Sometimes this problem is more apparent on north-facing roof slopes that don’t heat up sufficiently for the shingles to seal until summer. Usually this isn’t a major issue, but if you live in an area that is very windy, your roofer can apply temporary adhesive to prevent the wind from catching the edge of the unsealed shingles and blowing them off.