The Pacific Northwest offers ideal climate conditions for pouring concrete. The best concrete installations occur during times of overcast days and generally high humidity, which describes a good portion of the year around here. 

However, pouring concrete can be particularly challenging when the weather is excessively cold, hot or wet. Here are some tips for ensuring great concrete installations no matter the weather. 

Rainy weather 

Depending on the use of the concrete — whether it is for concrete stairs or a concrete sidewalk, for example — the right ratio of water, cement and gravel is critical. Too much or too little water, and you could have a concrete installation that is weak and doesn’t last as long as it should. 

Thus, it’s important when pouring concrete that you try not to let too much rainwater fall into the mix. Don’t pour concrete into areas with standing water, and be sure to cover the concrete as soon as it is finished to keep the concrete hydrated while also ensuring that a hard rain doesn’t mar the concrete surface. Don’t finish any standing rainwater into the surface of the concrete. 

Here are more tips for pouring concrete in the rain. 

Cold weather 

In cold weather, it’s critical that ice crystals do not form on or within the concrete, as that can reduce the concrete’s strength. In addition, you don’t want the substrate, form boards, tools or anything else that will touch the concrete to be covered in frost or ice. 

According to Concrete Network, temperatures below 40 F for prolonged periods can lower the strength of concrete, meaning that the Pacific Northwest requires special concrete mixture and curing considerations. In addition, keep in mind that concrete poured in temps below 40 can take much longer to reach the required strength, so don’t remove your forms too early. 

Winter temps can hover around freezing for days on end in Whatcom County, and those freeze-thaw cycles can really wreak havoc on concrete during the curing process. Concrete that is subjected to repeated freezing and thawing can have problems with spalling and scaling, so consider using concrete admixtures when pouring concrete in cold weather. 

For a good overview on how best to pour concrete in winter, check out this page from 

Warm weather 

Warm and/or hot weather isn’t often an element of concern in Whatcom County. However, as we saw just recently, temperatures in the 90s and even 100s are possible. 

In hot weather, evaporation can occur too quickly, resulting in what is called “plastic” shrinkage cracking, with spidering cracks appearing while the concrete is still in its plastic, or fresh, state. 

The key in hot weather is to keep the surface of the concrete moist after placement. Sunshades can help slow evaporation, and misting can help keep the surface moist. 

To ensure your concrete installation is as durable, safe and good-looking as possible, sometimes it’s best to call in the experts. Custom Concrete Contracting serves clients in Bellingham, Ferndale, Lynden, Burlington and throughout Whatcom and Skagit counties.