# Pouring and Curing Concrete in Cold or Hot Weather Temperature limits, freeze protection, hot-weather drying, and curing time for a new slab, with a worked example. Guide page: (published 2026-10-05, updated 2026-10-05). This Markdown version has the guide's key points, outline, FAQs and sources; the full article, with its worked examples and diagrams, is on the page. ## Key takeaways - Cold slows the chemical reaction that hardens concrete; heat, sun, wind, and dry air pull water out of it too early. - Protect fresh concrete from freezing for at least the first 48 hours: QUIKRETE calls for plastic sheeting and insulation blankets if temperatures may drop below 32 °F. - An NIH bulletin, quoting ACI, treats air at or below 40 °F during the protection period as cold weather. - QUIKRETE Concrete Mix should be cured for 5 days at 70 °F or warmer, or 7 days at 50 to 70 °F, starting as soon as possible. - In hot, windy weather, apply curing sooner: QUIKRETE's Cure & Seal can go on 2 to 3 hours after placing instead of the usual 4 to 6. ## In this guide 1. [Why temperature matters](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#why-temperature-matters) 2. [The temperatures to watch](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#temperature-thresholds) 3. [Pouring in cold weather](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#pouring-in-cold-weather) 4. [Pouring in hot, dry, or windy weather](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#pouring-in-hot-weather) 5. [How long to cure, and how](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#how-long-to-cure) 6. [Worked example: a 10 × 12 ft slab in cool weather](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#worked-example) 7. [Before you pour: a weather checklist](https://www.howmanyyardsdoineed.com/guides/concrete-in-cold-and-hot-weather/#before-you-pour) ## Frequently asked questions ### What is the lowest temperature you can pour concrete in? There is no single cutoff. An NIH bulletin quoting the American Concrete Institute treats air at or below 40 °F during the protection period as cold weather, which calls for precautions. QUIKRETE adds that fresh concrete must not freeze in its first 48 hours. ### How long does concrete take to cure? For QUIKRETE Concrete Mix, the data sheet says to start curing as soon as possible and continue for 5 days at 70 °F or higher, or 7 days between 50 °F and 70 °F. Other products publish their own times. ### What happens if fresh concrete freezes? Early freezing can do permanent damage: the NIH bulletin says concrete can lose up to 50% of its ultimate strength. It recommends protection until the concrete reaches 500 psi, about 48 hours for most concrete kept at 50 °F. ### When should I apply cure and seal in hot weather? QUIKRETE's Acrylic Cure & Seal normally goes on 4 to 6 hours after placing, once the surface water has gone. In hot, windy weather that can drop to 2 to 3 hours; in cool weather wait at least 10 to 12 hours. ### Why does concrete crack in hot weather? If water evaporates from the surface faster than it rises from the concrete below, the surface shrinks and cracks while still plastic. FHWA paving guidance calls for fogging or an evaporation retarder when evaporation tops 0.2 lb per square foot per hour. ### Can I use a curing compound on a slab poured in late fall? QUIKRETE says not on surfaces where de-icers will be used that winter, because the compound can keep the concrete from air drying, which it needs to resist de-icer damage. Use another curing method instead. ## Related calculators and guides ### Calculators - [Concrete Calculator](https://www.howmanyyardsdoineed.com/concrete-calculator/) — Slab volume in cubic feet, cubic yards, and cubic meters, with ready-mix order size and bag counts for documented products. ### Guides - [How to Pour a Concrete Slab](https://www.howmanyyardsdoineed.com/guides/how-to-pour-a-concrete-slab/) — Plan, form, mix, place, finish, joint, and cure a slab, following the manufacturer's published method. - [Concrete Bag Yields by Bag Size](https://www.howmanyyardsdoineed.com/guides/concrete-bag-yields/) — Published cubic-foot yields for bagged concrete mixes, with bags per cubic foot, cubic yard, and cubic meter. - [How to Plan a Bulk Material Delivery](https://www.howmanyyardsdoineed.com/guides/planning-material-delivery/) — Rounding to supplier increments, questions to ask, and a checklist before bulk material arrives. ## Sources - [QUIKRETE Concrete Mix (No. 1101) product data sheet: installation, application, and curing](https://www.quikrete.com/pdfs/data_sheet-concrete%20mix%201101.pdf) — QUIKRETE Companies. Used for: Control joints 1 in deep every 6–8 ft; water about 6–9 pt per 80 lb bag; cure 5 days at 70 °F or higher, 7 days at 50–70 °F; protect from freezing for 48 h. Checked 2026-10-05. - [QUIKRETE Concrete Mix (No. 1101) product data sheet: curing in hot, cold, dry, and windy weather](https://www.quikrete.com/pdfs/data_sheet-concrete%20mix%201101.pdf) — QUIKRETE Companies. Used for: No curing compound if rain or temperatures below 50 °F are expected within 24 h; no curing compound in late fall where de-icers will be used. Checked 2026-10-05. - [QUIKRETE Acrylic Concrete Cure & Seal – Satin Finish (No. 8730) product data sheet](https://www.quikrete.com/pdfs/data_sheet-acrylic%20concrete%20cure%20and%20seal%208730.pdf) — QUIKRETE Companies. Used for: 200 ft²/gal as a curing compound; apply 4–6 h after placing, 2–3 h in hot windy weather, at least 10–12 h in cool weather; not if rain, heavy dew, or \< 50 °F expected within 24 h. Checked 2026-10-05. - [Cold Weather Concreting (Technical Bulletin, Issue 111, April 2021)](https://orf.od.nih.gov/TechnicalResources/Documents/Technical%20Bulletins/21TB/Cold%20Weather%20Concreting%20-%20April%202021%20Technical%20Bulletin_508%20.pdf) — National Institutes of Health, Office of Research Facilities. Used for: Protect from freezing until 500 psi (about 48 h at 50 °F); cold weather = air at or expected below 40 °F during the protection period; early freezing can cost up to 50% of ultimate strength. Checked 2026-10-05. - [Curing Practice for Slipformed Concrete Pavements (TechBrief FHWA-IF-06-003, October 2005)](https://www.fhwa.dot.gov/pavement/pccp/pubs/06003/06003.pdf) — Federal Highway Administration. Used for: Evaporation above 0.2 lb/ft²/h (1.0 kg/m²/h) calls for preventive measures such as fogging or an evaporation retarder. Checked 2026-10-05. - [QUIKRETE Concrete Mix (No. 1101) product data sheet](https://www.quikrete.com/pdfs/data_sheet-concrete%20mix%201101.pdf) — QUIKRETE Companies. Used for: 40 lb = 0.30 ft³; 60 lb = 0.45 ft³; 80 lb = 0.60 ft³; 90 lb = 0.675 ft³ (regional). Checked 2026-10-03. **Estimate only.** Results are planning estimates computed from the numbers you enter. They are not engineering, structural, or code advice. Confirm quantities, product yields, and installation requirements with your supplier, the product label, and your local building authority before you order or build.