The weather is a jobsite hazard in every season, and the injuries it causes are predictable, which means they are preventable. Heat drops people in summer, ice and cold stress do it in winter, and storm season can wreck a site and everything on it overnight. Plan for the season you are in and you avoid the emergencies. Here is the short version for each, with the deeper detail linked where it exists.
Summer: heat is the one that kills
Heat illness is the season's real danger, and it moves fast, from cramps to exhaustion to heat stroke, which is a medical emergency. The essentials are water, rest, shade, and acclimatizing new or returning workers gradually over their first days. This has its own full guide because it matters most and because several states have their own enforceable heat rules. See Heat illness: know the signs, and check Working in Your State for state-specific requirements.
Do not forget the slow summer hazard either: sun exposure and skin cancer build up over years (covered in Long-term health).
Winter: cold, ice, and frozen ground
Three winter hazards catch crews out:
- Cold stress. Hypothermia and frostbite are real risks, and wind chill makes them worse than the thermometer says. Dress in layers you can adjust, keep dry (wet clothing pulls heat out fast), take warm-up breaks, and keep eating and drinking, since you dehydrate in the cold too. Know the signs: uncontrollable shivering, slurred speech, and confusion mean get the person warm and get help. Numb, waxy, or white skin is frostbite, so warm it gradually and do not rub it.
- Slips and falls on ice. Icy scaffold, ladders, and walkways cause a spike in winter injuries. Clear and grit access routes, wear proper footwear, and slow down. Ice on height access is a serious fall risk (see Your rights on an unsafe site).
- Cold-weather concrete. Concrete does not cure properly in the cold and can be ruined by freezing. As a rule, protect fresh concrete when temperatures are around or below 40 degrees, use blankets or heated enclosures, and never pour on frozen ground. Plan pours around the forecast.
Shorter daylight also means you are more likely to be working in poor light, so light the site properly rather than pushing on in the dark.
Storm and wildfire season: protect the site before it hits
Depending on where you work, that is hurricanes and tropical storms, tornadoes, flooding, or wildfire. The common thread is that the danger and the damage are largely avoidable with preparation:
- Secure the site before a storm. Tie down or remove loose materials and debris that become missiles in high wind, secure or lay down scaffold and temporary structures, and move or protect tools and equipment (which also cuts theft, since empty storm-shut sites are targets, see Tool theft and security).
- Know your local risk and the warnings. Have a plan for stopping work and getting everyone off site safely when a warning is issued. Never gamble a crew against an incoming storm to save a day.
- After the event, treat the site as hazardous until checked: downed power lines, unstable structures, floodwater, and contamination are all common post-storm dangers.
The move
Look at the forecast the way you look at the plans. Match your PPE, your schedule, and your site setup to the season, and build the weather into your program rather than reacting to it. Local rules and risks (state heat standards, regional storm and wildfire exposure) are in Working in Your State.
Common questions
At what temperature is it too cold to pour concrete?
As a rule, protect fresh concrete when temperatures are at or below about 40 degrees Fahrenheit, because concrete does not cure properly in the cold and can be ruined if it freezes. Use insulating blankets or heated enclosures, never pour on frozen ground, and plan pours around the forecast. Follow the mix data sheet, and for critical pours get an engineer's guidance.
What are the first signs of cold stress or hypothermia on site?
Uncontrollable shivering, slurred speech, and confusion mean a worker is getting dangerously cold, so get them warm and get help. Numb, waxy, or white skin is frostbite: warm it gradually and do not rub it. Wind chill makes all of this worse than the thermometer reads, and wet clothing pulls heat out fast, so keep dry and take warm-up breaks.
Do I have to give my crew water and rest breaks in the heat?
The core of heat safety is water, rest, shade, and letting new or returning workers acclimatize gradually over their first days, and heat illness moves fast from cramps to exhaustion to heat stroke, which is a 911 emergency. Several states have their own enforceable heat rules on top of that, so check Working in Your State for what is required where you work.
How do I protect my tools and site before a storm?
Secure or remove loose materials and debris that turn into missiles in high wind, lay down or tie off scaffold and temporary structures, and move or lock away tools and equipment. Protecting the site also cuts theft, since a storm-shut site sitting empty for days is a target. Have a plan to stop work and get everyone off site safely the moment a warning is issued.
Is it safe to work right after a storm or flood?
No, not until the site has been checked. Treat it as hazardous: downed power lines, unstable structures, floodwater, and contamination are all common after a storm and each can kill. Never gamble a crew against an incoming storm to save a day either. Your local storm and wildfire risk varies, so build the regional threat into your plan (see Working in Your State).
The honest bit
- The cold-weather concrete guidance and cold-stress signs here are standard industry and OSHA/NIOSH practice, but manufacturers' mix specs and local conditions vary. Follow the mix data sheet and, for critical pours, an engineer.
- State heat rules and regional storm risk vary a lot. Confirm yours in Working in Your State.
- This is general guidance, not medical or engineering advice. In a heat or cold medical emergency, call 911.
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