Extreme heat continues to be a major workplace safety issue across California. During summer 2026, Cal/OSHA repeatedly reminded employers to protect workers as triple-digit temperatures affected Southern California, the Central Valley, the Sacramento Valley, and other inland regions.
California workplace heat safety rules cover both outdoor and indoor employment. The requirements can affect construction crews, agricultural workers, landscapers, warehouse employees, manufacturing workers, delivery operations, and many other workplaces where employees may be exposed to dangerous heat.
California Has Separate Indoor And Outdoor Heat Standards
California regulates outdoor heat exposure under Title 8, Section 3395 and indoor heat exposure under Section 3396. Employers may need to comply with both standards when their operations include indoor and outdoor work areas.
The rules focus on preventing heat illness before a worker becomes seriously sick. Employers are expected to plan for hot conditions, provide appropriate cooling measures, train employees, and establish procedures for responding when someone begins showing signs of heat illness.
Cal/OSHA provides an extensive collection of heat illness prevention resources for employers and employees.
Outdoor Workers Need Water, Shade, Rest And Training
California’s outdoor heat standard applies broadly to outdoor workplaces. Employers must provide fresh, suitably cool drinking water and make it readily accessible to workers. Cal/OSHA guidance explains that employers should provide enough water for each employee to drink at least one quart per hour.
Shade is another major requirement. When the outdoor temperature exceeds 80 degrees Fahrenheit, qualifying shade must be available while employees are present. Workers must also be allowed and encouraged to take preventative cool-down rests when they feel the need to protect themselves from overheating.
High-Heat Procedures Begin At 95 Degrees
At 95 degrees Fahrenheit or higher, employers in specified industries must implement additional high-heat procedures. These include maintaining effective communication, observing workers for signs of heat illness, designating people who can contact emergency services, reminding employees to drink water, and conducting pre-shift meetings.
Additional requirements can apply to agricultural employees during high-heat conditions.
[Suggested Internal Image 1 — Place Here]
Indoor Workplaces Have Heat Requirements Too
Heat hazards are not limited to outdoor jobs. Warehouses, commercial kitchens, manufacturing plants and other enclosed workplaces can become dangerously hot even when employees are not exposed to direct sunlight.
California’s indoor heat standard generally applies to covered workplaces when the indoor temperature reaches 82 degrees Fahrenheit. More extensive assessment and control requirements can apply when temperatures or the heat index reach 87 degrees, or under certain conditions at 82 degrees, including work involving clothing that restricts heat removal or areas with significant radiant heat.
Employers must provide access to drinking water and at least one cool-down area. That area must be shielded from direct sunlight and maintained at a temperature that allows workers to recover from heat exposure.
Temperature Monitoring Can Be Required
Covered employers may need to measure temperatures or heat index values and evaluate environmental risk factors. Effective control measures can involve engineering controls, administrative controls, work practices, or other measures appropriate to the workplace.
A warehouse, for example, may need ventilation, fans, cooled rest areas, changes to work schedules or other measures depending on the conditions employees experience.
Written Heat Illness Prevention Plans Matter
California’s heat standards require employers to establish and maintain written heat illness prevention procedures. The plan should address drinking water, shade or cool-down areas, rest periods, acclimatization, emergency response, employee training and other applicable requirements.
For outdoor workplaces, the plan must be available at the worksite. California also requires plans to be written in English and in the language understood by the majority of employees.
Training Should Happen Before Exposure
Employees and supervisors must understand the signs and symptoms of heat illness, workplace risk factors, emergency procedures, access to water and cooling, and the importance of reporting symptoms quickly.
Training becomes particularly important when a heat wave arrives suddenly or when employees have recently started working in hotter conditions.
Acclimatization Helps Reduce Heat Risk
The human body needs time to adjust to working in high temperatures. California’s outdoor standard requires close observation during heat waves and for employees newly assigned to high-heat areas.
New employees, workers returning after time away, and employees suddenly exposed to significantly hotter weather may face elevated risk because they have not yet acclimatized.
Employers should not assume that an experienced worker is automatically prepared for every heat event. Workload, humidity, direct sunlight, protective clothing, radiant heat, and other factors can significantly increase heat stress.
[Suggested Internal Image 2 — Place Here]
Recognizing Heat Illness Can Prevent An Emergency
Heat-related conditions can range from cramps and exhaustion to life-threatening heat stroke. Warning signs may include heavy sweating, dizziness, weakness, headache, nausea, confusion, fainting, unusual behavior, or loss of consciousness.
Severe symptoms require immediate action. California’s rules require effective emergency-response procedures so workers can quickly contact supervisors and emergency medical services when necessary.
A worker showing possible serious heat illness should not simply be sent away alone. Employers need procedures for monitoring the employee, providing appropriate first aid, and obtaining emergency assistance when required.
Heat Safety Is An Ongoing Workplace Responsibility
California heat requirements are not limited to the hottest afternoon of the year. Employers should monitor conditions, update procedures, maintain water and cooling resources, train new workers, and adjust operations when temperatures rise.
Current requirements and educational resources are available through Cal/OSHA’s outdoor heat illness prevention program.
Heat is also connected to broader California safety planning. Property owners may want to review our guide to California Zone 0 wildfire rules, while transportation readers can explore California’s 2026 autonomous vehicle safety rules.
Final Thoughts
California has some of the country’s most detailed workplace heat protections. The basic goal is prevention: workers need water, opportunities to cool down, appropriate training, emergency procedures, and additional protections when temperatures become dangerous.
Because indoor and outdoor standards differ, employers should identify which requirements apply to each work area rather than relying on a single summer safety policy. Employees can also benefit from understanding the protections that should be available when work conditions become dangerously hot.