A “good” temperature depends entirely on what you’re measuring. Normal body temperature for a healthy adult averages around 97.8°F to 98.6°F (36.6°C to 37°C), though the old 98.6°F standard is now considered slightly too high. For your home, 68°F to 72°F (20°C to 22°C) is comfortable for most people during the day. For sleep, cooler is better: 60°F to 67°F (15°C to 19°C). And for food safety, the numbers shift dramatically depending on whether you’re cooking or storing.
Here’s a breakdown of the key temperature ranges that matter most in daily life.
Normal Body Temperature
The 98.6°F standard dates back to 1851, when a German physician took millions of temperature readings from 25,000 patients. That number stuck for over 150 years, but modern research tells a different story. A large analysis of over 35,000 patients found the average oral temperature is closer to 97.9°F (36.6°C). A study published in eLife found that men born in the early 1800s had body temperatures about 1°F higher than men today, with a steady decline of roughly 0.05°F per decade. Women showed a similar pattern. Human body temperature has dropped about 1.6% since the pre-industrial era, likely due to lower rates of chronic inflammation and changes in metabolism.
Your own temperature naturally fluctuates throughout the day. It’s lowest in the early morning and rises toward the evening. The healthy range spans from about 97°F to 99°F (36.1°C to 37.2°C), and where you fall within that window depends on your age, activity level, and the time of day you take the reading. Infants and young children tend to run slightly warmer than older children and adults.
When Body Temperature Signals a Fever
Most healthcare providers define a fever as an oral temperature at or above 100.4°F (38°C). Readings between 99.5°F and 100.3°F (37.5°C to 37.9°C) are generally considered a low-grade fever. These thresholds are slightly higher for infants and toddlers, since their baseline temperatures tend to be warmer.
Best Room Temperature for Sleep
Your bedroom should be between 60°F and 67°F (15°C to 19°C) for the best sleep quality. That range helps stabilize REM sleep, the stage most closely linked to memory consolidation and feeling rested. Anything above 70°F is too warm, and below 60°F is too cold for most people. Your core body temperature naturally dips at night as part of your circadian rhythm, and a cool room supports that process rather than fighting it.
If 60°F sounds chilly, layering with breathable bedding lets you keep the air cool while staying comfortable. The goal is cool air on your face and head with enough covering to avoid waking from cold.
Comfortable Indoor Temperature
For daytime living spaces, the World Health Organization considers air temperatures between 64°F and 75°F (18°C to 24°C) safe for healthy, sedentary adults. Most people find 68°F to 72°F (20°C to 22°C) the sweet spot for comfort and productivity. Below 64°F, you may start to see negative health effects, particularly for elderly people or those with respiratory conditions.
Safe Cooking Temperatures
Undercooking food is one of the most common causes of foodborne illness, and the minimum safe internal temperatures vary by protein:
- Poultry (chicken, turkey, duck, whole or ground): 165°F (73.9°C)
- Ground beef, pork, lamb, or veal: 160°F (71.1°C)
- Fish and shellfish: 145°F (62.8°C)
These are the temperatures at which harmful bacteria are destroyed. An instant-read meat thermometer is the only reliable way to check, since color and texture can be misleading. Insert the probe into the thickest part of the meat, away from bone.
Refrigerator and Freezer Settings
Your refrigerator should stay at or below 40°F (4°C), and your freezer at 0°F (-18°C). Bacteria multiply rapidly between 40°F and 140°F, a range food safety experts call the “danger zone.” A fridge thermometer is worth having, since the built-in dial on many refrigerators isn’t precise. If your fridge feels like it’s barely cool, or your milk is spoiling before the expiration date, the temperature is probably too high.
Dangerous Outdoor Heat
When it comes to weather, temperature alone doesn’t tell the full story. The heat index combines air temperature with humidity to reflect how hot it actually feels to your body. The National Weather Service issues alerts based on heat index values: an excessive heat warning, the most serious level, means the heat index will be life-threatening within 24 hours, typically at readings of 105°F to 110°F (41°C to 43°C) or higher. Direct sun exposure can add up to 15°F to the heat index compared to shaded conditions, so the forecast number may understate your actual risk if you’re outdoors without shade.