At Polar Express, we get more emergency calls from June through September than any other stretch of the year. This is not because it’s hotter, but because it’s wetter. Central Florida homeowners tend to brace for their AC to work hard in July’s heat, but the rainy season brings its own set of problems that have nothing to do with temperature and everything to do with humidity, moisture, and lightning. 

Here’s what actually happens to your system during rainy season, and what you can do about it before it fails when you need it the most. 

Your AC Is Working Harder Than the Thermostat Lets On 

Cooling the air is only half of what your AC does. The other half is pulling moisture out of it. In Florida’s summer humidity, often 80 to 90 percent outdoors, a typical residential AC system produces 5 to 20 gallons of condensate per day, and over a full cooling season, a system may drain 1,500 to 3,000 gallons of water through a single small pipe.

During rainy season, that workload jumps even further. Summer storms bring sudden increases in outdoor moisture that can overwhelm condensate systems, and even overnight, humidity levels remain comparatively high at 60 to 80 percent. This means your system rarely gets a real break, even after the sun goes down. 

When weather is mild and dry, a system cycles on and off, giving the evaporator coil and drain pan time to dry out between cooling cycles. But sustained high humidity forces the system to run for extended periods, so the drip pan and drain line never get a chance to dry out. That constant moisture is exactly the environment where problems start. 

The Condensate Line Is Where Most Rainy-Season Failures Begin 

The condensate drain line is a narrow PVC pipe most homeowners never think about until it clogs. This line is a dark, damp, warm environment, exactly the conditions in which algae, mold, and mildew thrive. Algae that begins growing in spring can become a partial clog by early summer and a full blockage by July if the line isn’t cleared at the start of the season. 

When that happens, the consequences show up fast. Warning signs include a sudden, unexplained system shutdown, water pooling around the base of the indoor unit, a musty odor from the vents, or a gurgling sound near the air handler.

Modern systems are designed to shut down automatically once a clog is detected, usually through a float switch. That float switch protects the system by turning it off if water levels get too high — without it, even a simple clog can rapidly escalate into a major, urgent repair.

Left unaddressed, the growth can worsen the clog, increasing the risk of flood damage or moisture seeping into electrical components, which can cause further damage. 

Lightning Is the Other Rainy-Season Threat Most People Don’t See Coming 

Central Florida doesn’t just get rain during rainy season; it gets some of the most frequent lightning in the country. Orlando is the lightning capital of the country, averaging over 100 thunderstorm days every single year, and it only takes one nearby strike to send a massive spike of voltage through a home’s wiring, frying sensitive circuit boards in seconds. 

The real danger often isn’t the strike itself. During a severe summer thunderstorm, power outages are common, but the real danger isn’t the power going out; it’s the power coming back on when the grid restores electricity and often sends a massive, momentary voltage spike straight into a home’s wiring.  

Modern systems are more exposed to this than older ones. A newer AC system with a variable-speed compressor drive, a communicating control board, and multiple capacitors and sensors operates at low signal voltages that are extremely sensitive to transient over-voltage.

A surge that an older, single-stage unit might have survived can destroy the control board on a newer communicating system. Warning signs of surge damage include a system hesitating or struggling to start, clicking or buzzing sounds from failing capacitors or contactors, or the system shutting off unexpectedly and short cycling. Compressor damage is the costliest outcome. Compressor failure is often the most expensive repair associated with lightning damage, and it can frequently necessitate a complete system replacement. 

How to Actually Prep for Rainy Season 

The fixes here aren’t complicated, but they need to happen before the season ramps up, not after a system fails during a storm. 

• Have your condensate line cleared and inspected before June 

• Confirm your float switch is functioning 

• Install surge protection on your outdoor condenser unit 

• Keep up with routine maintenance year-round, not just before summer 

The Bottom Line 

Central Florida’s rainy season punishes AC systems in ways summer heat alone never does — through relentless moisture, clogged drain lines, and lightning-driven power surges. A little prep before the season starts, especially a condensate line inspection and surge protection, is the difference between a system that coasts through the rain and one that fails right when you need it most. 

Beat the storms — call Polar Express at (321) 263-1351.