Your Body Almanac

California

Wildfire smoke, valley fever dust, inland heat and year-round sun.

California's risks depend on where you live, but a few reach most of the state. Wildfire smoke can cover huge areas for days, valley fever is at record levels in the Central Valley and Central Coast, inland summers are very hot, and the sun is strong most of the year.

01

Wildfire smoke

Large wildfires can send smoke across much of the state, far from the flames. The fine particles in smoke reach deep into your lungs and can cause coughing, burning eyes and headaches, and trigger asthma attacks and heart problems. Children, older adults, pregnant people and anyone with lung or heart disease are most at risk.

SourcesHow Wildfire Smoke Affects Your Body (CDC)Wildfires and Smoke (AirNow)
Check the air qualityAs neededLook up your local Air Quality Index before outdoor work or exercise, and scale back when it is high. Wear a respirator for dust, fumes and smokeAs neededUse a properly fitted N95 or better respirator for dusty work and heavy wildfire smoke, and a cartridge respirator for gases and vapors.
02

Valley fever from soil dust

Valley fever is a lung infection from a fungus in the soil. You breathe in spores when dirt is disturbed by wind, digging, farming or construction. Most California cases come from the Central Valley and Central Coast, and the state reported nearly 12,500 cases in 2024, its highest on record. Outdoor workers who disturb soil face the most exposure.

SourcesValley Fever (California Department of Public Health)About Valley Fever (CDC)
Wear a respirator for dust, fumes and smokeAs neededUse a properly fitted N95 or better respirator for dusty work and heavy wildfire smoke, and a cartridge respirator for gases and vapors. Check the air qualityAs neededLook up your local Air Quality Index before outdoor work or exercise, and scale back when it is high.
03

Inland heat

The Central Valley and desert regions see long stretches of triple-digit heat. Without a chance to cool off overnight, your body falls behind, and heat exhaustion can turn into heat stroke.

SourcesHeat Safety (National Weather Service)About Heat and Your Health (CDC)
Stay safe in the heatAs neededOn hot days, drink water often, take breaks in the shade and plan hard work for the cooler parts of the day. Drink water through the dayDailyKeep a water bottle within reach and sip through the day instead of waiting until you are thirsty. Rehydrate when you sweatAs neededDrink regularly during hot work or long workouts, and add electrolytes when you sweat for more than two hours.
04

Strong sun most of the year

Clear skies and a southern latitude keep UV levels high for much of the year, and UV reflects off sand, water and snow. Mountain areas add more UV with altitude. Skin damage adds up with every unprotected hour.

SourcesSun Safety Monthly Average UV Index (US EPA)Sun Safety (CDC)
Wear sunscreen every dayDailyPut broad-spectrum SPF 30+ on exposed skin each morning and reapply every two hours outdoors. Wear sun-protective clothingAs neededCover up with a wide-brimmed hat, UV-blocking sunglasses and tightly woven long sleeves when you are out in the sun. Check your skin for changesAs neededLook over your whole body on a regular schedule for new spots or moles that change, itch or bleed.

When to see a professional

Ask a doctor about valley fever if a cough, fever or fatigue lasts more than a week or two, especially after time around dust. Chest pain or trouble breathing on smoky days needs medical care.