Why temperature matters
Concrete does not dry. It hardens through a chemical reaction between cement and water, and that reaction is sensitive to temperature.
- Below about 40°F the reaction slows to a crawl. If fresh concrete freezes in its first day or two, it can be permanently weakened.
- From 50°F to 75°F is ideal. The concrete gains strength steadily and the crew has time to finish it properly.
- Above 85°F to 90°F, with sun and wind, the surface can dry faster than the concrete underneath sets, which leads to surface cracks. Crews handle this by pouring at dawn and keeping the slab damp.
The season, month by month
| When | What to expect |
|---|---|
| March to mid-April | Frost is leaving the ground and the soil is soft and wet. Tear-outs can start, but concrete should never be poured on frozen or saturated ground. A good time to get estimates and a place in the schedule. |
| Late April to June | Good pouring weather and the busiest stretch of the year. Rain causes the odd delay. |
| July and August | Reliable and dry. On hot days expect an early-morning pour and extra attention to curing. |
| September to mid-October | Arguably the best conditions of the year: mild days, cool nights and a little less demand. |
| Late October to November | Still workable while nights stay above freezing, with blankets on standby. The catch is that the slab gets very little time before its first winter. |
| December to February | Most residential crews stop. Winter pours are possible with heated concrete, insulated blankets and enclosures, but they cost more and are rarely worth it for a driveway. |
The catch with late fall
New concrete is at its most vulnerable to deicing salt in its first winter. The usual guidance is to give it about a month of drying after curing before salt touches it. A driveway poured in early November gets that month if you keep salt off it yourself, but you cannot stop the street's slush from riding in on your tires. If you pour late, plan to rinse the apron on mild days and read our first-winter care guide.
When to ask for estimates
For a spring driveway, ask in February or March. Contractors build their spring schedule over the winter, and the first warm week brings a flood of calls. People who already have a signed estimate get poured in April and May. People who call in May are often looking at July.
For a fall pour, ask by August. If your project needs a permit or an association's approval, add a few weeks for that.
Does it matter if it rains?
Light rain a few hours after finishing does little harm, and damp weather in the following days helps curing. Heavy rain during the pour or the finishing is the problem, because it washes cement out of the surface. A careful contractor watches the forecast and will move your date before risking it. That is a good sign, not a nuisance.
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