A relative humidity of 68% is high for indoors and noticeably uncomfortable outdoors. The EPA recommends keeping indoor humidity between 30% and 50%, and considers anything above 60% a moisture problem. At 68%, you’re well past that threshold, entering territory that promotes mold growth, dust mites, and potential damage to your home.
Whether you’re reading a hygrometer in your living room or checking the weather app, 68% humidity signals that moisture levels deserve attention. What that means for your comfort, health, and home depends on the context.
68% Humidity Indoors: Too High
The EPA’s ideal indoor range is 30% to 50% relative humidity, with 60% as the upper boundary before problems start. At 68%, you’re 8 percentage points above that ceiling. This isn’t a gray area. You’ll likely notice the air feels damp, fabrics feel clammy, and your home may develop a musty smell.
At this level, conditions are favorable for mold colonies to establish themselves on walls, ceilings, window frames, and anywhere moisture lingers. Mold spores are always present in indoor air, but they need sustained humidity above 60% to settle and grow. A home sitting at 68% gives them exactly that. Bathrooms, basements, and poorly ventilated closets are the first places you’ll see visible growth, but it can spread behind drywall and under flooring where you won’t notice it right away.
Dust mites thrive at this humidity too. Research has shown that maintaining indoor humidity below 51% dramatically reduces dust mite populations. In one study, homes that kept humidity under that level for 17 months saw live mite counts drop from about 400 per gram of dust to just 8. At 68%, you’re creating the opposite condition: a warm, moist environment where mite colonies flourish in bedding, carpets, and upholstered furniture.
How It Feels Outdoors
Outdoor humidity of 68% can range from barely noticeable to oppressive depending on the temperature. Relative humidity is, as the name suggests, relative to air temperature. The same 68% reading feels very different at 65°F than at 90°F.
The better measure of outdoor comfort is dew point, which tells you the actual amount of moisture in the air regardless of temperature. The National Weather Service breaks it down simply: dew points below 55°F feel dry and comfortable, 55°F to 65°F starts to feel sticky with muggy evenings, and anything above 65°F feels oppressive. If the temperature is 85°F and relative humidity is 68%, the dew point is around 73°F, which is firmly in the “oppressive” category. Your sweat can’t evaporate efficiently, so your body struggles to cool itself.
On a cooler day, say 60°F with 68% humidity, the dew point drops to about 49°F. That’s perfectly comfortable. So outdoors, 68% humidity is high in warm weather and unremarkable in cool weather.
Health Effects at This Level
Sustained indoor humidity around 68% can trigger or worsen respiratory issues. High humidity disrupts the protective lining of your airways, impairing the ability of tiny hair-like structures in your lungs to clear mucus. This makes you more vulnerable to allergic reactions and can worsen asthma symptoms. The combination of impaired airway function, increased mold spores, and higher dust mite allergens creates a triple threat for anyone with allergies or respiratory sensitivity.
Sleep quality takes a hit as well. Your body naturally lowers its core temperature as you fall asleep, and humid air makes this harder. Research on sleep in humid conditions found that high humidity significantly reduced the amount of deep sleep and REM sleep people got, while increasing the time they spent awake during the night. The effect was most pronounced when both temperature and humidity were elevated, but humidity alone plays a measurable role. If your bedroom sits at 68% humidity on a warm night, expect more restless, less restorative sleep.
Signs Your Home Is Too Humid
You don’t need a hygrometer to spot the clues, though owning one (they cost under $15) removes the guesswork. Condensation on windows is one of the earliest visible signs. With double-pane windows, you’ll start seeing moisture on the glass when indoor humidity is around 40% and outdoor temperatures drop below zero. At 68% indoor humidity, condensation can appear on windows, mirrors, and cold pipes even in mild weather.
Other signs include a persistent musty or damp smell, peeling wallpaper, warping wood, and visible mold spots in corners or around window frames. Wood flooring is particularly sensitive. Manufacturers recommend keeping humidity between 35% and 55% to prevent planks from absorbing moisture and swelling. At 68%, hardwood floors can cup, buckle, or develop gaps as they go through cycles of absorbing and releasing moisture.
How to Bring It Down
A dehumidifier is the most direct solution. Portable units work well for single rooms, while whole-house dehumidifiers connect to your HVAC system and manage moisture throughout the home. Set your target to 45% to 50%, which keeps you comfortably within the recommended range while leaving a buffer below the 60% problem zone.
Air conditioning naturally dehumidifies as it cools, which is why indoor humidity often drops when you run the AC. If you’re seeing 68% humidity despite running air conditioning, your system may be oversized (cooling the air too quickly without enough run time to pull out moisture), your ductwork may have leaks, or you may have a significant moisture source like a wet crawl space or plumbing leak.
Ventilation helps in the right conditions. Running exhaust fans during and after showers and cooking removes moisture at the source. Opening windows works only when outdoor humidity is lower than indoor levels. On a muggy summer day, opening windows will make the problem worse. Simple habits also matter: avoid drying clothes indoors, fix any leaking pipes promptly, and make sure your dryer vents to the outside rather than into the house.
If your home regularly climbs above 60% despite these measures, it’s worth checking for hidden moisture sources. Water intrusion through the foundation, poor grading around the house directing rainwater toward the walls, or a failing vapor barrier in the crawl space can keep humidity stubbornly high no matter how many dehumidifiers you run.