What is the recommended temperature range for placing concrete in moderate climates?

• A. Roughly 50 to 90°F (10 to 32°C).
• B. 0-20°F
• C. 100-120°F
• D. 40-60°F

Answer: (A)

Temperature controls how fast concrete hydrates and then cures. In moderate climates, you want a placing window that supports steady hydration without excessive moisture loss or slow setting, which helps achieve good strength and finishability. Roughly 50 to 90°F (10 to 32°C) provides that balanced range, accommodating typical daily temperature swings and allowing proper curing practices to work effectively.

Placing concrete at freezing or near-freezing temperatures (0–20°F) risks freezing and delayed strength gain, while temperatures that are too hot (100–120°F) speed up evaporation and hydration so much that plastic shrinkage, cracking, and finishing problems become more likely. A narrower range such as 40–60°F is too restrictive for many moderate-climate days, making the broad 50–90°F window the most practical choice for general placement.