Can You Leave a Generator Outside in the Rain or Snow?
A portable generator is designed to operate outdoors—but that does not mean it can safely run uncovered in rain or snow. Water entering the generator’s outlets, wiring, control panel, or alternator can create an electrical-shock hazard, trip breakers, damage components, and shorten the generator’s life.
The safest approach is to operate the generator outdoors in a dry, well-ventilated location while using a weatherproof running cover or properly designed open-sided canopy. Never move a running generator into a garage, shed, porch, basement, or other enclosed or partially enclosed space to protect it from the weather.
Quick Answer
You should not leave a portable generator exposed to rain or snow while it is running. If generator power is needed during bad weather, use a cover specifically designed for operating generators—not an ordinary storage cover, tarp, garage, or enclosed shed.
The generator should be:
- At least 20 feet from the house
- Away from doors, windows, and vents
- Positioned with its exhaust facing away from buildings
- Protected from rain and snow without restricting airflow
- Placed on a dry, level surface
- Surrounded by several feet of open space
- Connected only with outdoor-rated cords and equipment
The Consumer Product Safety Commission recommends operating portable generators outdoors at least 20 feet from the house and never on a porch or in a carport. The exhaust should point away from the house and other occupied buildings. See the CPSC generator safety guidance.
Why Can’t a Generator Get Wet?
A portable generator produces enough electricity to cause serious injury. When water reaches the outlets, plugs, electrical connections, or internal components, it increases the risk of electric shock and equipment failure.
Rain and melting snow can cause:
- Electrical shock
- GFCI or circuit-breaker trips
- Short circuits
- Corrosion
- Damage to the control panel
- Damage to the alternator or inverter electronics
- Unstable electrical output
- Premature generator failure
Important Safety Warning
A generator can still be dangerous even if it appears to operate normally after getting wet. Moisture may remain inside its receptacles or electrical components.
OSHA advises keeping generators dry and not operating them in rain or wet conditions. When weather protection is necessary, OSHA recommends using a canopy while maintaining sufficient clearance for ventilation. See the OSHA portable-generator safety guide.
Can You Run a Generator in the Rain With a Cover?
You may be able to operate a generator during rain if you use a weatherproof running cover specifically designed for your type and size of generator.
A proper generator running cover should:
- Keep rain away from the outlets and control panel
- Protect the generator from water coming from different directions
- Allow engine heat to escape
- Provide adequate combustion air
- Leave the exhaust completely unobstructed
- Remain securely attached during wind
- Be made from heat-resistant material
- Allow safe access to the controls and fuel tank
Use a Running Cover, Not a Storage Cover
Follow both the generator manufacturer’s instructions and the cover manufacturer’s compatibility requirements. A cover that fits poorly could trap heat, block airflow, contact the muffler, or direct exhaust toward the operator.
Never place an ordinary storage cover over a running generator. Storage covers are normally intended only for generators that are turned off and completely cool.
Can You Put a Tarp Over a Running Generator?
A loose tarp is generally not a good generator shelter.
A tarp can sag, collect water, blow against the hot muffler, restrict cooling air, or channel water toward the outlets. It may also collapse under accumulated snow.
If a tarp is used as an emergency overhead canopy, it must be supported independently of the generator and positioned high enough to preserve airflow and exhaust clearance. Its sides should remain open. The tarp must not touch the generator, and water must drain away from the equipment.
A purpose-built running cover is a safer and more dependable choice than an improvised tarp.
Can You Run a Generator in a Garage With the Door Open?
No—Never Run a Generator in a Garage
Never operate a portable generator inside a garage, even if the main garage door is completely open.
Carbon monoxide can accumulate inside the garage and enter the house through doors, walls, attic spaces, or other openings. Wind can also push exhaust back into the building.
For the same reason, do not operate a generator in a:
- Basement
- Shed
- Carport
- Porch
- Breezeway
- Crawlspace
- Trailer
- Partially enclosed structure
Opening doors and windows does not make these locations safe. Carbon monoxide is colorless and odorless, and dangerous concentrations can develop before anyone recognizes the problem.
The CDC recommends placing a generator at least 20 feet from windows, doors, and vents in an area where rain and snow cannot reach it. The agency also recommends battery-operated or battery-backup carbon-monoxide detectors inside the home. See the CDC winter-weather generator guidance.
Can You Run a Generator in a Shed?
An ordinary shed is not a safe place to operate a portable generator. Opening the shed door does not provide reliable protection from carbon monoxide, overheating, or fire.
A professionally designed generator enclosure is different from a typical storage shed. A safe operating enclosure must be designed for the particular generator and include appropriate:
- Combustion-air openings
- Cooling airflow
- Exhaust routing
- Heat-resistant materials
- Fire clearances
- Weather protection
- Electrical access
- Manufacturer-required clearances
Do not assume that adding vents or an exhaust hose makes a homemade wooden shed safe. Exhaust modifications can create backpressure, leak carbon monoxide, or violate the generator manufacturer’s instructions.
How Should You Protect a Generator From Snow?
Snow presents several problems beyond falling moisture. Wind can blow fine snow into outlets and ventilation openings, while drifting snow can obstruct the engine or exhaust. Snow can also melt beneath the generator and create standing water.
When operating a generator in snow:
- Place it on a stable, elevated, noncombustible surface.
- Use a compatible running cover or open-sided weather canopy.
- Keep the generator at least 20 feet from occupied buildings.
- Point the exhaust away from the house and neighboring structures.
- Clear snow away from the intake, cooling openings, and exhaust.
- Prevent snow from accumulating on the cover.
- Keep cords and connections out of puddles and melting snow.
- Do not touch plugs or controls while your hands are wet.
- Check the generator periodically for drifting snow.
- Maintain working carbon-monoxide detectors inside the home.
Never place a generator directly in deep snow. The machine’s heat can melt the snow, causing it to settle unevenly or sit in water.
Does Cold Weather Hurt a Generator?
Cold temperatures do not automatically prevent a portable generator from operating, but they can make starting and operation more difficult.
Cold weather may cause:
- Thicker engine oil
- Reduced battery performance
- Hard starting
- Carburetor icing under certain conditions
- Snow or ice blocking ventilation
- Frozen control cables or switches
- Condensation inside electrical components
Use the oil viscosity recommended in the owner’s manual for the expected temperature. If the generator has an electric starter, keep its starting battery charged and maintained.
Do not use an unapproved heater, heat lamp, open flame, or combustible blanket to warm the generator. Manufacturer-approved cold-weather kits may be available for some models.
What Should You Do if Your Generator Gets Wet?
If a generator becomes wet, do not continue operating it or immediately attempt to restart it.
Steps to Take After a Generator Gets Wet
- Shut the generator down if it can be done without entering standing water or touching wet electrical equipment.
- Disconnect the electrical loads after power has been shut off.
- Move the generator to a dry location only after it has cooled.
- Allow it to dry thoroughly.
- Inspect the outlets, plugs, cords, control panel, and wiring.
- Check for water inside the air-filter housing and fuel system.
- Have the generator professionally inspected if it was soaked, submerged, or exposed to flooding.
Do not use electrical equipment that has been submerged. Floodwater can leave contamination and conductive residue behind even after the equipment appears dry.
Can a Generator Be Stored Outside?
A generator can sometimes be stored outdoors, but only if it is properly protected from moisture, sunlight, pests, and temperature extremes.
For outdoor storage:
- Turn the generator off and allow it to cool completely.
- Use a fitted weather-resistant storage cover.
- Store it on a dry, elevated surface.
- Keep it away from standing water.
- Protect it from roof runoff and snow accumulation.
- Follow the manufacturer’s fuel-storage instructions.
- Inspect it regularly for rust, rodents, and moisture.
- Never cover a generator while its engine or muffler is hot.
Storage and operation are different. A garage may be suitable for storing a cooled generator, but it is never a safe place to run one.
Long-term storage in a dry garage or shed is generally better for the equipment. Gasoline should be stored separately in approved fuel containers and according to local fire-safety requirements. Do not keep large quantities of gasoline inside the living area of a home.
What Is the Safest Generator Setup for Bad Weather?
A dependable bad-weather setup should be prepared before the outage begins.
A good setup includes:
- A level concrete pad or other stable, noncombustible base
- A purpose-built weatherproof running cover
- At least 20 feet of separation from the house
- Exhaust directed away from all buildings
- Heavy-duty outdoor-rated extension cords
- Dry and protected cord connections
- A properly installed generator inlet and transfer equipment when powering house circuits
- Working carbon-monoxide detectors on every level of the home
- Adequate fuel stored safely in approved containers
- A flashlight for nighttime inspection
Plan where the generator will operate before severe weather arrives. Moving a heavy generator, arranging cords, and building a shelter during a storm creates unnecessary risk.
Generator Weather-Safety Checklist
Before starting the generator, confirm that:
- ✓ The generator is outdoors.
- ✓ It is at least 20 feet from the house.
- ✓ It is not in a garage, shed, porch, or carport.
- ✓ Rain and snow cannot reach its electrical components.
- ✓ The shelter does not trap exhaust or heat.
- ✓ The exhaust points away from buildings.
- ✓ The unit has adequate open space around it.
- ✓ The surface is dry, level, and stable.
- ✓ The cords are outdoor-rated and undamaged.
- ✓ Connections are protected from water.
- ✓ Your hands and the control panel are dry.
- ✓ Carbon-monoxide detectors are operating inside the home.
Frequently Asked Questions
Will rain ruin a portable generator?
Rain may damage the outlets, wiring, control panel, alternator, or inverter electronics. Even when permanent damage does not occur, operating wet electrical equipment can expose the user to electric shock.
Are portable generators waterproof?
Most portable generators are not waterproof. Some components may resist light moisture, but that does not mean the unit is approved for uncovered operation in rain or snow. Check the owner’s manual for the manufacturer’s exact restrictions.
Can I cover my generator with a plastic tote?
No. A plastic tote can restrict airflow, trap heat, deform, contact hot surfaces, and allow carbon monoxide to accumulate around the generator. Use an approved running cover or properly designed open-sided canopy.
Can I operate a generator under a deck?
Operating beneath a deck is risky because exhaust may collect under the structure or enter the house. The deck may also expose the generator to water runoff. Choose a fully outdoor location at least 20 feet from the house instead.
Can extension-cord connections lie on the ground?
Connections should be kept dry and elevated above puddles, snow, and wet soil. Use outdoor-rated cords and weather-resistant connection protection designed for the purpose.
Should I bring the generator inside during a storm?
You may bring a generator inside for storage after it is shut down and cool, but never operate it indoors. If it cannot be operated outdoors while remaining dry, it should remain off until safe weather protection is available.
Bottom Line
A portable generator must operate outside, but it should not be left exposed to rain or snow. Use a purpose-built running cover or properly designed open-sided canopy that keeps the electrical components dry without restricting cooling or exhaust.
Keep the generator at least 20 feet from the house, point the exhaust away from buildings, use outdoor-rated electrical equipment, and maintain working carbon-monoxide detectors inside. Never use a garage, shed, porch, or carport as a substitute for safe weather protection.
Preparing a safe outdoor operating location before the next storm will make it much easier to use your generator correctly when the power goes out.