When to Pour Concrete in Kansas Weather

What concrete needs after it is placed

Concrete hardens through a chemical reaction with water called hydration, not by drying out. NRMCA's curing guidance says curing should begin right after finishing and typically continue for 3 to 7 days, that the temperature of placed concrete should be kept above 50 degrees, and that concrete in a dry environment can lose as much as half its potential strength compared with moist-cured concrete (NRMCA, CIP 11: Curing In-Place Concrete). So the question is not just "can it be poured?" but "can it be kept moist and warm enough for the next several days?"

The Wichita calendar

NWS Wichita's normals give the frame (NWS Wichita, annual climate normals for Wichita, Salina and Chanute):

• Average last spring freeze (32°F): about April 9.
• Average first 90-degree day: about May 22.
• Average last 90-degree day: about September 28.
• Average first fall freeze (32°F): about October 25.
• About 65 days a year reach 90 degrees and about 12 reach 100.

NOAA's monthly normals add detail: average lows climb from about 45 degrees in April to 56 in May, and average highs fall from about 83 in September to 71 in October (NOAA NCEI 1991–2020 monthly normals, Wichita Eisenhower airport station). That leaves two comfortable windows: roughly mid-April through May, and mid-September through mid-October.

The NWS freeze page also shows how much the dates vary. The typical range for the first fall freeze at Wichita runs from about October 20 to November 4, and the earliest on record was in late September (NWS Wichita, frost and freeze information). Averages are a guide, not a promise.

Cold-weather pours

NRMCA defines cold weather as a period when, for more than three consecutive days, the average daily temperature is below 40 degrees and the air stays at or below 50 degrees for more than half of any 24 hours (NRMCA, CIP 27: Cold Weather Concreting). In those conditions it calls for special precautions. Key points from its guidance:

• Fresh concrete freezes below about 25 degrees, and freezing can reduce its potential strength by more than half.
• New concrete should be protected from freezing until it reaches about 500 psi, roughly two days after placement.
• Concrete exposed to freeze-thaw cycles should be protected until it reaches about 3,500 psi.
• A 20-degree drop in concrete temperature roughly doubles setting time.
• Snow and ice should be removed, and the ground and other surfaces the concrete touches should be above freezing before placement.

Insulating blankets, heated enclosures, warm concrete from the plant and accelerating admixtures are standard tools. They work, but they add steps, and an outdoor slab poured in late fall still faces its first freeze-thaw season young. For decorative patios and driveways that will see salt, many homeowners prefer to wait for spring.

Hot-weather pours

NRMCA's hot-weather guidance explains that high air and concrete temperatures, low humidity, wind and sun speed moisture loss and setting. Hot concrete needs more water, loses slump faster, can lose entrained air and, cured hot, ends up weaker at later ages than concrete cured around 70 degrees (NRMCA, CIP 12: Hot Weather Concreting). It recommends planning deliveries so trucks can discharge immediately, avoiding the hottest part of the day, and not sprinkling water on slabs to ease finishing.

Wind is a local wild card. NWS lists Wichita's average wind speed at about 11.5 mph (NWS Wichita, annual climate normals for Wichita, Salina and Chanute). NRMCA's plastic shrinkage guidance says those surface cracks are likely when high evaporation dries the surface before the concrete sets, and recommends windbreaks, fog sprays and covering the concrete between finishing steps (NRMCA, CIP 5: Plastic Shrinkage Cracking). A breezy July afternoon is a classic setup for them.

Rain

May and June are Wichita's wettest months in NOAA normals, at about 5.2 and 4.9 inches (NOAA NCEI 1991–2020 monthly normals, Wichita Eisenhower airport station). Rain on fresh concrete can wash out the surface and ruin a finish. Pours are usually scheduled around forecasts, with plastic sheeting on hand. A rain delay of a day or two is normal in spring.

Month by month at a glance

Scheduling realities

The comfortable windows are also the busiest. Booking a spring pour in late winter, or a fall pour in summer, makes it easier to land on the calendar you want. Whatever the season, ask how the estimate plans for weather: curing method, cold or hot protection, and what happens if rain is forecast.

See the freeze-thaw guide for why first winters matter, and the estimate factors page for how seasonal protection changes a scope.

Planning a fall slab? Read why the first winter matters first.

Sources: NWS Wichita, annual climate normals for Wichita, Salina and Chanute; NWS Wichita, frost and freeze information; NOAA NCEI 1991–2020 monthly normals, Wichita Eisenhower airport station; NRMCA, CIP 27: Cold Weather Concreting; NRMCA, CIP 12: Hot Weather Concreting; NRMCA, CIP 5: Plastic Shrinkage Cracking; NRMCA, CIP 11: Curing In-Place Concrete.