The ideal time to lay asphalt is when it is hot during the day and the night temperatures are moderate and, of course, when there is no rain. However, you can't always predict when rain is going to make a surprise appearance. Gravel is easily washed away if it rains heavily.
Rain, Rain, Go Away!
You can't seal your new asphalt driveway right away because the asphalt must cure first before sealing can be applied. Sealing provides protection from the elements. If you lay asphalt in the summer, it is inevitable that it is going to get rained on at some point, although hopefully not as much as if you were to lay it in the fall. According to Rhinehartasphaltpaving.com, a new asphalt driveway should be sealed before bad weather arrives because the seal will protect the driveway from damage caused by the elements. But, then again, you cannot seal the same day that you lay asphalt. You must wait three months or even longer.
Rain can't be avoided in the long term although it is certainly better for it not to occur when asphalt is newly laid. Ultimately, rain and sunshine together are going to dry out asphalt and wear it out. Asphalt loses its flexibility and gets brittle with age. Even if the asphalt is somehow not exposed to the elements, it will get dry over time and become lighter in colour. If rainwater goes all the way through the asphalt, it is going to wash away the foundation, which is the gravel base, and this lessens structural support.
Rain causes weathering and ravelling, which is the loss of aggregate from the surface. Water combined with vehicular and foot traffic cause extreme ravelling, which also can occur if you have paved too late in the season or if the asphalt is poorly compacted. Additionally, overheating of the asphalt in the plant where it was made or using too little asphalt can result in ravelling.
Ideally, it should be hot and dry when you lay asphalt, but if it does rain afterward you may see low spots in the asphalt that are referred to as bird baths. If the spots are deep,
this could be a problem. To find out if the indentation is going to be problematic, fill the low spot with water and drop a quarter into it, advises Allaboutdriveways.com. If the water doesn't cover the quarter, then the low spot shouldn't be a problem. If it does, this means there may be problems in the future. Contact the person who installed your asphalt, and let him make a determination if something should be done to correct this low spot.