Seasonal

Pouring Concrete in Cold Weather

There is no date in any code that closes the season. There are two temperature thresholds that do real work, and a protection requirement that matters more than either of them. Here is what actually governs a late pour.

Updated October 2026 · Gurnee Concrete

Ring round for a driveway quote in October and you will be told, in several different ways, that the season is finishing. It is worth knowing what that statement is and is not. It is a scheduling position, and frequently a reasonable one. It is not a rule from a code, because no code contains a calendar date for concrete. That distinction is the difference between waiting until May because it is genuinely better and waiting until May because nobody explained the options.

The two numbers that are real

Where the industry does put figures down, they are temperatures:

Source	Threshold
ACI 306R-16	Cold-weather concreting practice begins at 40F
WisDOT specification 415	Placement suspended below 35F on a falling thermometer

Notice what those say. The first does not prohibit anything; it says that below 40F a different set of practices applies. The second is a state highway specification, so it is stricter than a residential job needs to be, and even that one is written against a thermometer rather than a diary.

Notice also what neither of them mentions: October, November, or any month at all.

The part that matters more than the pour day

Concrete gains strength through a chemical reaction that generates its own heat and slows down as it gets colder. That is manageable. What is not manageable is fresh concrete freezing before it has developed enough strength to resist the expansion, because the damage that does is internal, permanent and cannot be repaired later.

So the real question about a late pour is never simply how cold it is on the day. It is what happens to the slab over the nights that follow, and whether anybody has planned for them. A pour at 45F with three clear frosty nights afterwards and no protection is a worse decision than a pour at 38F that is properly covered.

What cold-weather practice actually involves

• Ground that is not frozen. Concrete does not go onto frozen base. When the ground thaws underneath, everything above settles with it.
• Insulating blankets over the slab, holding the heat the concrete is generating rather than letting it go to the sky overnight.
• Mix adjustments, which can mean a different cement content or an accelerator so the early strength arrives sooner.
• Attention to the edges. Slab edges and corners lose heat from more than one face and are where cold-weather damage shows up first.
• A finishing plan that expects delay. Cool concrete stays workable longer, which sounds convenient and mostly means a long cold day for the crew waiting to finish it.
• The forecast, not the morning. Several days of it.

All of that costs something, and it is the honest reason autumn quotes sometimes come in higher or come with conditions attached. A contractor who says a late pour needs protection and prices it in is telling you the truth. One who says it simply cannot be done in November is telling you about their calendar.

The winter after, which nobody warns you about

If your slab goes down late in the year, the single most important thing to know has nothing to do with the pour. Use no deicer at all through the first winter. Rock salt is the obvious one to avoid. The trap is the advice that follows it, because the two products usually recommended as the gentler substitute, calcium chloride and magnesium chloride, both appear on the industry's list of what should never go onto concrete, and in laboratory testing the magnesium one came out worst of the lot for strength loss. A great deal of national advice has this precisely the wrong way round.

Sand for grip. Shovel rather than treat. A young slab that gets through its first winter clean will take what comes afterwards.

How we would actually advise you

If it is early autumn, book it. The ground is dry, the crews are still running, and you get a surface that is fully cured and ready before spring.

If it is late in the year and the forecast is settled, it can still be a good pour with protection planned and priced in, and we will tell you what that adds rather than quietly absorbing it.

If it is genuinely cold, wet and unsettled, the right answer is to wait, and we would rather say that than take the job. Waiting has a cost too, because spring fills up and early-season ground is the wettest of the year, so the useful move is to get the design and the quote settled now and hold a slot rather than starting the conversation in April with everybody else.

The sequence and the specification do not change with the month, and both are described on our concrete driveway page. For the money side, with every assumption named, read the Gurnee driveway cost breakdown.