Can You Pour Concrete in Winter in Spokane? Cold-Weather Rules, Cure Times and What We Do Differently (2026)

Yes, you can pour concrete in a Spokane winter, but not the way you pour it in July. The concrete has to be kept from freezing until it's strong enough to survive it, it can't go on frozen ground, and it cures more slowly in the cold. Here's what the industry standards say, what Spokane's weather actually looks like from November to March, and how that changes a driveway, patio, shop slab or footing job.

When "cold weather" rules kick in

The American Concrete Institute's cold-weather guide (ACI 306R-16) says cold-weather concreting conditions exist when the air temperature has fallen to, or is expected to fall below, 40°F during the protection period, meaning the days right after the pour when fresh concrete can be damaged by cold.

By that definition, most of Spokane's late fall, winter and early spring counts. NOAA's 1991–2020 normals for Spokane International Airport show:

• November: average low 30.3°F, average high 42.3°F, about 19 nights at or below freezing
• December: average low 24.3°F, average high 33.8°F, about 27 nights at or below freezing and 13 days that never get above 32°F
• January: average low 24.7°F, average high 34.5°F, about 26 freezing nights
• February: average low 26.3°F, average high 39.5°F, about 23 freezing nights
• March: average low 31.5°F, average high 48.6°F, about 19 freezing nights

Even October and April average 7 to 8 nights at or below 32°F, so shoulder-season pours need a plan too.

The 500 psi rule: why the first two days matter most

Fresh concrete is full of water. If it freezes before the cement has used up enough of that water, the ice expands and permanently weakens the slab and its air-void system. ACI's guidance is clear:

• Protect concrete from freezing until it reaches at least 500 psi. At that point it has dropped below the saturation level where a single freeze causes damage
• At 50°F, most well-proportioned mixes reach 500 psi within about 48 hours
• If the concrete will see repeated freeze-thaw cycles while saturated, ACI says to protect it until it reaches 3,500 psi, which matters for driveways, aprons and patios that sit wet under snow

That's why a winter pour lives or dies on the first couple of days, and why the forecast decides our pour dates in December and January.

Never pour on frozen ground

The International Residential Code (Section R403.1.4.1) says footings shall not bear on frozen soil unless the frozen condition is permanent. Spokane's seasonal frost isn't permanent. When it thaws in spring, the ground under a footing or slab that was poured on frost can settle and crack the concrete.

Spokane-area footings already have to sit at least 24 inches below finished grade under the City of Spokane / Spokane County joint frost-depth policy (deeper in some towns, such as Deer Park's 36 inches). In winter we also have to make sure the bottom of the excavation and the gravel base aren't frozen when the concrete goes in. If they are, the ground has to be thawed and kept covered until the pour.

How long concrete takes to cure in the cold

Cold slows the chemical reaction that makes concrete strong. ACI 306R-16's protection table for ordinary Type I cement shows how much:

• To reach 50% of its 28-day strength: about 6 days at 50°F, compared with 4 days at 70°F
• To reach 65%: about 11 days at 50°F, compared with 8 days at 70°F
• To reach 85%: about 21 days at 50°F, compared with 16 days at 70°F

Below 50°F it's slower still. In practice that means a winter driveway may need to wait longer before you drive on it, and a shop slab may need more time before the steel or framing crew loads it. We'll give you a time based on the mix and the weather, not a summer rule of thumb.

What we do differently on a winter pour

ACI's cold-weather guide lays out the tools, and these are the ones that matter on residential and shop work:

• Pick the pour window: we schedule around the forecast so the first 48 hours are as mild as possible
• Thaw and protect the subgrade: no concrete on frozen soil, snow, ice or standing water
• Warm concrete from the plant: ready-mix suppliers heat water and aggregates in winter so the concrete arrives at a safe temperature
• Faster-setting mixes: accelerating admixtures and higher early-strength mixes shorten the protection time. ACI warns that calcium chloride accelerators can corrode reinforcing steel over time, so we're careful about what goes into reinforced slabs
• Insulated blankets and poly sheeting: sheeting alone cuts heat loss and keeps moisture in, and blankets hold the heat the concrete makes as it cures
• Heated enclosures for footings and walls when needed: with care, because ACI notes winter air dries concrete quickly once it's heated
• No water curing in the cold: ACI says wet curing at the end of the protection period can leave the concrete saturated right when it's exposed to freezing
• Pull the blankets off gradually: ACI recommends letting the surface temperature drop over about 24 hours to avoid thermal cracking

The first winter after a pour

Whether your concrete went in last June or last week, its first winter is the riskiest one for the surface. ConcreteState, a ready-mix industry group, recommends:

• No chemical deicers at all the first winter. Use plain sand for traction
• Never use deicers containing ammonium nitrate or ammonium sulfate, which rapidly disintegrate concrete. Calcium chloride, magnesium chloride, magnesium acetate and magnesium nitrate have also been found to damage concrete
• Watch the fertilizer: some garden fertilizers contain ammonium nitrate or ammonium sulfate
• Seal it: apply a concrete sealer after finishing

Spokane's freeze-thaw cycles are why our exterior flatwork uses an air-entrained mix in the first place. Our guide to driveway repair vs. replacement covers what scaling and freeze-thaw damage look like later.

Should you wait until spring?

Sometimes. Here's how we usually think about it:

• Footings and shop slabs under a building: often worth pouring in winter if the building is coming and the ground can be thawed and protected, so the project doesn't lose months
• Interior slabs inside an enclosed building: the easiest winter pour, because the space can be protected and heated
• Driveways, patios and decorative or stamped work: more weather-sensitive, so we may suggest a spring date unless you need it now
• Shoulder-season pours (October, early November, March, April): very doable with blankets and a careful look at the overnight lows

Planning a shop? Read our shop slab thickness guide and our PEMB lead-time guide, since many winter pours are for buildings arriving in spring.

Get a winter or spring concrete quote

Call 509-350-2016 or request a free quote with your project, size and address, and we'll tell you honestly whether it should go in now or wait for warmer weather. See our concrete flatwork services.

Sources

• ACI 306R-16, Guide to Cold Weather Concreting (excerpt)
• American Concrete Institute FAQ, What is the effect of freezing on concrete?
• ACI Resources, Cold Weather Concrete
• NOAA NCEI 1991–2020 Monthly Normals, Spokane International Airport
• IRC R403.1.4 frost protection requirements (summary of R403.1.4.1)
• City of Spokane / Spokane County Joint Policy BUILD-07, Official Frost Depth
• City of Deer Park Municipal Code 15.04, Building Codes (design criteria)
• ConcreteState, Concrete Deicer Warning