Concrete has the least forgiving weather window of any trade: temperature, evaporation, and rain timing all have to line up. CrewCast checks your pour-day forecast hourly and can warn you the evening before.
| Factor | Ideal | Trouble |
|---|---|---|
| Temperature | 50–70°F pour range | <40°F curing stalls / freeze risk · >90°F high crack risk |
| Evaporation | Humid, calm, mild | Hot + dry (RH <40%) + wind >15 mph = plastic shrinkage cracking |
| Rain | None until finish + initial set | Rain dilutes the surface, ruins finish — cover or reschedule |
The sneaky one is evaporation risk: a 88°F afternoon with 35% humidity and a 16 mph breeze will crack a slab that a hotter-but-humid day wouldn't. CrewCast computes the combined heat + dryness + wind risk (per ACI hot-weather guidance) instead of making you juggle three numbers.
Set your trade to Concrete in CrewCast's alerts and you'll get a push notification the evening before any day whose work-window forecast is a no-go — before the truck is scheduled, not after it's rolling.
Below 40°F, hydration slows dramatically and freeze damage becomes possible; cold-weather concreting (blankets, heated water, accelerators) is required. The comfortable pour range is roughly 50–70°F.
Yes with precautions up to about 90°F, but above that crack risk climbs fast. Hot-weather practice: pour early morning, chill the mix, use retarders and windbreaks, and cure aggressively.
Rain during finishing washes cement paste from the surface and weakens/ruins the finish. Light rain after final set is generally harmless. Always have covering ready if rain probability is meaningful.
It samples tomorrow's hourly forecast across the work window (7 AM–4 PM) and runs the same temperature/evaporation/rain rules the in-app score uses. If enough work hours fail, it pushes you an evening heads-up.