What is the ideal temperature range for pouring concrete in New Brunswick?

The ideal temperature range for pouring concrete in New Brunswick is 15-25°C air temperature, with concrete delivered at 18-22°C — conditions that are reliably found in NB from late June through mid-September. In this range, hydration proceeds at a normal rate, working time is generous, and surface moisture loss is manageable without special precautions.

Within this range, everything about a concrete pour works as it should. The concrete arrives at the right temperature from the ready-mix plant, it flows and consolidates properly, the hydration reaction proceeds steadily, and the finishing window is long enough for the crew to work through large pours without rushing. Strength gain follows the standard curve: roughly 70% of design strength at 7 days, 85-90% at 14 days, and full 28-day strength on schedule. This is the range that NB's May through September window reliably delivers, with the peak sitting squarely in June, July, and August.

Below 15°C, concrete begins to work less predictably. The hydration reaction slows noticeably below 10°C, extending curing time and requiring more attention to post-pour temperature monitoring. NB mornings in May and September can start in the 8-12°C range, which is borderline — fine if daytime temperatures reach 15-20°C and overnight stays above 5°C, but worth monitoring closely.

Above 25°C, evaporation rates rise and the risk of plastic shrinkage cracking increases. The concrete's working time shortens. NB summer heat waves push into the 28-32°C range several times per year in the July-August period, requiring precautions like early morning pours and evaporation retarder — but these are manageable conditions, not stop-work conditions.

Air temperature is only one part of the picture. Substrate temperature matters equally — a gravel base that started the morning at 5°C will pull heat from the concrete even on a 20°C day. Wind dramatically increases surface evaporation regardless of temperature — a 20 km/h breeze on a 25°C day creates more evaporation risk than calm conditions at 30°C. Relative humidity affects how quickly the surface dries. Experienced NB concrete contractors evaluate all of these factors, not just the thermometer reading, before and during a pour.

For practical planning: if you are booking a concrete driveway, patio, or foundation in NB, the dates that give you the highest probability of ideal conditions are June 15 through September 15. This is when every factor — air temperature, substrate temperature, frost risk, precipitation patterns, and humidity — aligns most consistently for quality concrete work. The further you stray from this window in either direction, the more monitoring and active management your pour requires.

New Brunswick Concrete can connect you with local contractors who will assess your site-specific conditions and advise on the optimal timing for your project, whether it is in the heart of summer or at the margins of the NB concrete season.