Hot-mix asphalt needs to be laid hot and rolled hot. If the ground or air is too cold, the mat cools before the crew can compact it to density, and the surface ends up porous and weak. CT contractors generally need overnight lows above about 40°F and daytime highs of 50°F or warmer to lay a quality mat. That puts the practical season at mid-April through late October most years.
Some crews extend with shoulder-season tricks (warm-mix asphalt, working only on sunny afternoons, heated rollers), but the safer rule for a homeowner is to assume the season closes when overnight temperatures stop staying above freezing.
