Last verified: October 1, 2026
The Atlantic hurricane season runs from June 1 to November 30, and the best time to get your generator ready is May, before the first storm and before dealers get busy. That means booking any service that’s due, confirming the unit is in Auto and exercising, clearing the area around it, filling the propane tank, stocking oil and a filter, and planning how your household will use power. This guide gives you a month-by-month plan and checklists for standby and portable generators.
Why preparation matters more than the generator
In 2024, the average U.S. electricity customer went about 11 hours without power, and the EIA attributes about 80% of those hours to major events such as Hurricanes Beryl, Helene and Milton. Customers in South Carolina averaged nearly 53 hours. Long outages are exactly when small problems (a weak battery, an empty propane tank, a clogged vent, oil past its interval) turn into a generator that won’t run. See our power outages by state table for your area.
A simple season calendar
- April and May: book the dealer service if anything is due, replace an aging battery and look back over the exercise log.
- May: fill the propane tank; stock oil, a filter and fuel stabilizer; test any portable generator and practice the transfer procedure.
- June to November: watch the weekly exercise once a month, keep the vents clear and top up the propane after any real use.
- When a storm is forecast: work through the 24-hour checklist below.
- After the season: note the run hours and schedule an oil change if outage running brought you close to the interval.
Standby generator: before the season
- Check the service status. For Generac air-cooled units, oil and filter are due every 2 years or 200 hours, or every year or 100 hours in hot-weather continuous use, with a bigger service every 4 years or 400 hours. A Service A or Service B message on the controller means something is due. See the maintenance schedule.
- Check the battery. It’s one of the most common reasons a generator fails to start. If it’s several years old or the controller has warned about it, replace it now.
- Confirm Auto mode and the exercise log. The unit only starts automatically, and only exercises, in Auto.
- Clear the area. Generac’s manual says to remove shrubs and tall grass within 3 feet of the intake and exhaust louvers and to clear debris that collects inside the enclosure.
- Propane users: fill the tank. A 22 kW unit at half load burns about 2.5 gallons an hour, so a 500-gallon tank (400 usable) lasts roughly six and a half days. Deliveries slow sharply once a storm is forecast. See How Much Propane Does a Generator Use?
- Stock oil and a filter in the grade your manual specifies, for long outages.
- Check for water risks. Make sure downspouts, sprinklers and sump discharge don’t drain toward the unit. In flood zones, discuss protection with your installer; a generator that has been submerged must be checked before it runs again.
Portable generator: before the season
- Start it and run it under some load for 15–20 minutes.
- Change the oil if due; check the spark plug and air filter.
- Deal with old gasoline: use or dispose of fuel that has sat without stabilizer, and refill approved cans with fresh, stabilized fuel. Keep propane cylinders outdoors.
- Test the whole connection: inlet box, generator cord, interlock kit or transfer switch. Print the step-by-step procedure and keep it in the panel. See Interlock Kit vs Transfer Switch.
- Choose and mark the spot where it will run: outdoors, more than 20 feet from windows, doors and vents.
- Buy spare oil, a spark plug and enough cord.
Household preparation
- CO alarms: battery-backed carbon monoxide alarms on every level of the home and near bedrooms. Replace them as the manufacturer says, or about every 5 years per the CDC.
- A power plan: a written list of what you’ll run and in what order. Our size calculator shows what fits.
- Backup light and communication: flashlights, a battery radio, power banks.
- Contacts: your dealer’s emergency number, the generator’s model and serial numbers, and your gas or propane supplier saved in your phone.
- Medical needs: if someone depends on powered equipment, plan for a second backup (a battery power station) in case the generator needs repair.
The 24-hour checklist when a storm is forecast
- Top up propane, gasoline (portables) and oil.
- Check the standby unit: Auto mode, no alarms, vents clear.
- Secure outdoor furniture, trash cans and anything that could blow into the generator.
- Charge phones and power banks while utility power is still on.
- Turn the fridge and freezer to their coldest settings.
- Put the portable generator, cord and fuel where you can reach them safely in the dark.
During and after the storm
- Check the oil daily during long outages. Generac asks owners of air-cooled models to shut down for at least 30 minutes every 24 hours of continuous running to check and top off the oil. See How Long Can a Generator Run Continuously?
- Keep the vents clear of debris and standing water.
- Never move a portable generator into a garage or under a porch to keep it dry, even with the door open. Use a canopy made for running generators. See Generator Carbon Monoxide Safety.
- Manage loads to stretch fuel: stagger big appliances and raise the AC setpoint.
- After the outage, note the run hours and book an oil change if you’re close to the interval.
Frequently asked questions
Should I turn off the standby generator before a hurricane?
No. Leave it in Auto so it starts when the power fails. Only shut it down for maintenance or if flooding threatens the unit, following your manual and your installer’s advice.
Can I run my generator during the storm?
A properly installed standby generator is designed to run outdoors in bad weather. Portable generators must still stay outdoors and far from the house; never bring one inside to protect it from rain.
Before the first storm warning
Do the maintenance in spring, fill the fuel before the forecasts start, practice the connection procedure, and keep CO alarms working. A generator that’s ready in May is the one that runs in September.