Your first day hike: a practical checklist

The short answer

• Pick an easier trail than you think you can handle, and check the official park or forest page for closures and rules.
• Leave a trip plan with someone who is not going: your route, who is with you, and when you will be back.
• Carry the Ten Essentials, scaled to a day, with enough water and your own medicines.
• In heat, start early and turn back early. Higher up, go slowly and head down if you feel sick.
• Know your stop signs. Confusion in the heat, chest pain, or trouble breathing at rest mean call 911.

1. Before the day

• Choose a trail that suits the least experienced person in your group: check round-trip distance, climbing, shade and surface. Ask a ranger if unsure. Not walking regularly yet? Start with a walking routine.
• Check the official park or forest website for closures, alerts, fire restrictions, and permit or reservation rules for your date. In Yosemite and Sequoia and Kings Canyon, start with the park's "current conditions" page. Check again the morning you leave.
• Check the forecast for the trail, not your town. Sequoia and Kings Canyon warns a clear morning can turn stormy by midmorning.
• Check heat and air: the NWS HeatRisk map (0, green, to 4, magenta) and the Air Quality Index (AQI) at AirNow.gov. See what the AQI numbers mean.
• Download or print a map. The National Park Service (NPS) warns not to rely on a cell phone; there may be no signal. Airplane mode saves battery.
• Look up sunset and set a turnaround time (below).
• Leave a trip plan: route, contact information, start and return times, and who is with you. Use the printable day hike trip plan. NPS says hiking with a companion is safer; if you go alone, take extra steps to be prepared.

Setting a turnaround time. NPS advises planning at least twice as long for uphill stretches as for downhill ones, and being off the trail before dark.

2. What to pack: the Ten Essentials for a day

NPS says to carry these whenever you are outdoors.

Also pack:

• A whistle. Three blasts signal for help.
• Sturdy shoes. NPS suggests rubber-soled shoes or boots with ankle support on dirt and gravel; no flip-flops. Wool or synthetic socks, plus a spare pair.
• Insect repellent registered by the EPA, such as one with DEET or picaridin.
• A bag for trash, and toilet paper with a bag to carry it out.
• A card listing your emergency contact, conditions, medicines and allergies.

3. Water and food

• Carry enough. Yosemite advises at least 1 quart every 2 hours: 2 quarts for a 4-hour hike. Heat and steep climbs call for more.
• Drink regularly, and eat too. NPS advises drinking before you feel thirsty in hot weather. Grand Canyon's heat guidance adds: don't force fluids; rest and eat often. For long, sweaty effort, MedlinePlus suggests drinks with electrolytes.
• If a clinician limits your fluids or you take water pills (diuretics), ask how much to drink on a hot hike.
• Treat water you collect. Clear stream water can carry germs, such as the parasite Giardia. The CDC calls boiling the most effective method: a rolling boil for 1 minute, or 3 minutes above 6,500 feet. Many filters remove parasites but not viruses.
• Watch your urine. The CDC says light yellow or clear usually means enough. See dehydration in adults.

4. Heat and elevation

Foothill heat (Central Valley and lower Sierra)

Sequoia and Kings Canyon says summer and early fall temperatures at its lower elevations can top 100°F.

• Start at first light and finish before afternoon. Sun is strongest from 10 a.m. to 4 p.m. daylight saving time, and AirNow says ozone (smog) is worse in the afternoon and early evening.
• On a red or magenta HeatRisk day, or an orange AQI day if you have asthma or heart or lung disease, choose a shorter, shadier hike or another day.
• Wear loose, light-colored clothing. Feel faint or weak? Stop and get to shade.

More: heat-related illness in the Central Valley.

Higher elevations (Sierra Nevada)

Many Sequoia and Kings Canyon trails are above 5,000 feet. NPS warns that around 8,000 feet you risk altitude illness, which can be life-threatening.

• Day trips carry less risk. The CDC says the main risk comes from sleeping at 8,000 feet or higher, but symptoms can start within hours, and fitness does not protect you.
• Go slowly and reapply sunscreen; the sun is stronger up high.
• Warning signs: a headache plus nausea, dizziness, poor appetite or unusual tiredness. Rest and go no higher; head down if it gets worse.
• Danger signs: confusion, stumbling, unusual drowsiness, or breathlessness at rest. Go down right away and call 911.

5. Medicines and health conditions

• Carry medicines on you, not in the car. The CDC warns that heat can make inhalers burst, keep epinephrine auto-injectors from working properly, and weaken insulin.
• Ask about heat-sensitive medicines. The CDC lists water pills, several blood pressure and heart medicines, some antidepressants and antipsychotics, lithium, stimulants, and antihistamines such as diphenhydramine. Do not stop a medicine on your own. See medicines that can raise your risk in a heat wave.
• Diabetes: the CDC advises checking blood sugar before and after activity, which often lowers it. If your medicines can cause lows, carry fast-acting sugar and your meter, and teach a partner the signs. See recognizing low blood sugar.
• Asthma: pack your quick-relief inhaler and follow your action plan. See air quality and respiratory health in the Central Valley.
• Severe sting or food allergy: the American Academy of Allergy, Asthma & Immunology advises carrying two epinephrine devices (auto-injectors or nasal spray); after using one, you still need emergency care.
• Heart or lung disease, sleep apnea, sickle cell trait, pregnancy, or recent surgery: talk with a clinician first, especially before going high.

Questions for your clinician or pharmacist: Is this distance, climb and elevation reasonable for me? Do my medicines affect heat tolerance, heart rate or blood sugar? How much should I drink on a hot day? Which symptoms mean turn back, and which mean call 911?

6. On the trail

• Keep the group together, with the slowest hiker setting the pace. If you can talk while walking, the pace is about right.
• Keep your turnaround time, even short of the goal.
• Stay on the marked trail. Yield to uphill hikers; step to the downhill side for horses.
• Stay back from rivers and waterfalls. Sequoia and Kings Canyon says drowning is its most frequent cause of death; many victims fell in without meaning to swim.
• If you hear thunder, head for a building or car; no place outdoors is safe. If you can't reach one, the National Weather Service advises leaving peaks, ridges and open areas, avoiding lone tall trees, water and metal, and spreading out.
• Bears and food: Yosemite says keep at least 50 yards from bears and food within arm's reach. Car rules differ: Yosemite allows food in a closed car only in daylight; Sequoia and Kings Canyon says use the trunk at trailheads. Check each park's current food-storage rules before you go.
• Snakes, poison oak, ticks: rattlesnakes are common in Sequoia's foothills, so watch where you put your hands and feet. Poison oak has leaves in groups of three. Check for ticks afterward and shower within 2 hours, as the CDC advises.

7. If something goes wrong

• If you are lost: NPS advises calmly retracing your steps with your map. If you can't, call 911 and give the trail name, your last known location, landmarks, clothing colors and any medical conditions. Then stay put unless your life is in immediate danger. With no signal, add layers, find shelter, and signal with three whistle blasts. Help can take hours or days.
• If someone is hurt, NPS suggests sending two or more people for help while others stay.
• Snakebite: call 911 and remove rings and watches. The CDC says do not cut or suck the bite, apply a tourniquet or ice, or take alcohol, aspirin, ibuprofen or naproxen. Do not drive yourself.
• Cold and wet: Sequoia and Kings Canyon warns hypothermia can happen in any season, even around 60°F. Shivering, confusion, stumbling and sleepiness are signs. Get dry and add layers.

8. Leave No Trace

The Leave No Trace Seven Principles come from the Leave No Trace Center for Outdoor Ethics, and NPS promotes them. On a day hike, they come down to a few habits:

• Pack out everything, including food scraps and used toilet paper.
• If there is no toilet, NPS describes a hole 6 to 8 inches deep, at least 200 feet from water, trails and camps.
• Stay on the trail, leave rocks and plants where they are, and never feed wildlife.

Sources

1. 10 Essentials — National Park Service, updated May 28, 2026.
2. Hike Smart — National Park Service, updated June 13, 2024.
3. Outdoor Emergency Plan — National Park Service, accessed October 21, 2026.
4. Trail Safety — Sequoia & Kings Canyon National Parks, updated March 16, 2026.
5. River Safety and Current Conditions — Sequoia & Kings Canyon National Parks, updated June 26, 2024, and October 13, 2026.
6. Hiking Safety — Yosemite National Park, updated November 19, 2022.
7. Bears and Food Storage and Current Conditions — Yosemite National Park, updated March 14, 2024; Current Conditions accessed October 21, 2026.
8. Summer Hiking: Hike Smart — Grand Canyon National Park, updated June 26, 2026.
9. Heat Cramps, Exhaustion, Stroke — National Weather Service, February 25, 2025.
10. NWS HeatRisk — National Weather Service, accessed October 21, 2026.
11. About Heat and Your Health — Centers for Disease Control and Prevention, July 20, 2026.
12. Heat and Athletes — Centers for Disease Control and Prevention, June 25, 2024.
13. Heat and Medications: Guidance for Clinicians — Centers for Disease Control and Prevention, September 18, 2025.
14. High-Altitude Travel and Altitude Illness — CDC Yellow Book 2026, April 23, 2025.
15. About Water Treatment Options When Hiking, Camping, or Traveling — Centers for Disease Control and Prevention, January 30, 2025.
16. Sun Safety Facts — Centers for Disease Control and Prevention, June 17, 2026.
17. Preventing Tick Bites — Centers for Disease Control and Prevention, August 28, 2024.
18. Venomous Snakes at Work — CDC National Institute for Occupational Safety and Health, September 23, 2026.
19. Lightning safety when a safe building or vehicle is nearby — National Weather Service, accessed October 21, 2026.
20. AQI Basics and Air Quality Guide for Ozone — U.S. Environmental Protection Agency, AirNow, accessed October 21, 2026.
21. Get Active and Low Blood Sugar (Hypoglycemia) — Centers for Disease Control and Prevention, May 2024.
22. Low blood sodium — MedlinePlus, National Library of Medicine, reviewed May 19, 2025.
23. About Heart Attack Symptoms, Risk, and Recovery — Centers for Disease Control and Prevention, October 24, 2024.
24. Stinging Insect Allergy — American Academy of Allergy, Asthma & Immunology, July 29, 2026.
25. Text to 911: What You Need to Know — Federal Communications Commission, accessed October 21, 2026.
26. Leave No Trace Seven Principles — National Park Service, updated June 16, 2022; principles © 1999 Leave No Trace Center for Outdoor Ethics, www.LNT.org.