The Most Blistering Heatwave to Ever Hit San Bernardino County Was Suffocating

Written by Kristin Hitchcock
Updated: August 2, 2023
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The hottest heat wave to ever hit San Bernadino County, California was in July 1996, when temperatures hit 120 °F. That historic heat wave baked much of the West, hitting several records. Plus, it also caused health issues and damaged the power grid.

Of course, the county has also seen other heat waves. For instance, in June 2021, a brush fire erupted near Highway 18 due to the hot, dry conditions of the county. In July 2021, the desert areas faced temperatures up to 115 °F.

What counts as the “hottest heat wave” depends on who you ask. Some people take the average of all the heat wave days, while others only care about the hottest recorded temperature.

Interested in learning more about this heat wave and others? Then keep reading.

Historical Context

The average annual temperature in San Bernadino County is 63.3 °F. Usually, the hottest month is August, with an average high of 96 °F. However, heat waves can fall in any month.

San Bernadino County gets about 16.37 inches of rain on average. They get as much as an inch in February, which is the wettest month. The driest months tend to be in the summer, which is also when it is the hottest. Therefore, wildfires aren’t all that uncommon.

This county has had several heat waves over the year. During the month of September 2022, the Western region of the United States experienced an extreme heat wave that shattered numerous temperature records and posed significant threats to both public health and the power grid.

In October 2007, a series of wildfires ignited by strong Santa Ana winds burned more than 500,000 acres and 2,000 buildings in San Bernardino County, killing six people from heart attacks caused by the stress of evacuating. The wildfire wasn’t solely caused by the heat. However, it was a significant factor.

During June 2017, a heat wave broke all-time temperature records, with some areas of San Bernardino County reaching up to 112 degrees. The National Weather Service issued an excessive heat warning and urged people to stay cool and hydrated.

Another significant heat wave was on July 2021. However, it mostly affected dessert areas, which reached 115 °F.

San Bernadino County Heat Records

portrait of tired sick exhausted woman, beautiful girl is suffering from hot Summer heat stroke, sunshine, hot weather day, sweaty and thirsty, high temperature. Feeling unwell, unhealthy

The hottest temperature ever recorded in San Bernadino County was 120 °F.


On July 23, 1996, the highest temperature ever recorded in San Bernardino County was 120 °F. This occurred during a severe heat wave that impacted the entire Western region, causing numerous record-breaking temperatures and straining California’s power grid.

This particular heat wave was caused by a strong and persistent high-pressure system that trapped hot and dry air over the region, creating a dome of heat that intensified over time.

The heat wave worsened the region’s fire hazard and drought conditions while endangering public health and wildlife.

San Bernadino County Heat Wave Impacts


High temperatures in this county can lead to severe impacts on people. Here are some of the ways that these extra heat waves impact humans:

  • Illnesses and death. As you might imagine, extreme heat can cause illnesses, including heat exhaustion, heat stroke, dehydration, and similar issues. These can be life-threatening if not treated promptly, especially in at-risk people. According to a study by UCLA, San Bernardino County had the highest number of heat-related deaths in Southern California from 2006 to 2017, with 1,050 fatalities. Plus, for every 10 °F in heat increase, the mortality risk goes up by 2.5%.
  • Economic loss. This county gets a lot of income from tourism. However, no one wants to visit during a heat wave. Plus, heat waves can also impact agriculture and energy, leading to economic losses all around. For example, high temperatures can reduce crop yields, increase water demand, cause power outages, damage infrastructure, and deter visitors.
  • Ecological impacts. Heat waves also affect the environment, which we’ll discuss more below. However, these environmental effects also come around and affect people. For instance, wildfires and droughts can be directly and indirectly caused by heat waves and affect humans.

Luckily, there are many ways people can limit their risks, both personally and on a larger scale.

  • Stay hydrated. Many heat-related illnesses happen when people don’t stay hydrated. Therefore, drinking plenty of water, especially outside, can reduce health risks. It’s a simple step with a big impact.
  • Stay cool. Of course, the best way to prevent health issues is to reduce your exposure to heat. Cooling centers are often available during heat waves for this reason. You should seek air conditioning, wear light clothing, and watch pets and vulnerable people.
  • Reduce energy use. The power grid is often strained during heat waves, as everyone runs their air conditioning. Therefore, taking steps to conserve energy is recommended, such as setting your thermostat higher than you normally would and unplugging unnecessary appliances.
  • Prepare for emergencies. You never know when an emergency is going to occur. You should be prepared for heat-related illnesses by having emergency equipment nearby, such as cooling pads.
  • Build resiliency. Communities can limit heat-related problems by adapting to extreme heat. For instance, planting trees, installing cooling roofs, and volunteering can help the community.


Heat waves can also affect infrastructure in San Bernadino County. For instance, they can cause:

  • Power outages. High temperatures can stress the electricity demand, as everyone’s air conditioner will run full blast. Therefore, power outages can cause blackouts or brownouts, especially during the day. These power outages can disrupt essential services, including health care and transportation. For those who need electrical devices, these issues can be even worse.
  • Transportation issues. High temperatures can damage transportation infrastructure, like roads and bridges. For instance, heat waves can cause the pavement to crack and melt, creating hazards or even destroying roads. Rails can expand and warp and air travel can be disrupted.
  • Damage to buildings. Heat waves can also damage buildings. For instance, heat can cause roofs to expand and contract, leading to cracks. Heat can affect the lifespan of HVAC systems, increasing their maintenance costs. It may even cause fires in at-risk buildings.


High temperatures also affect the vegetation and animals in the county. Unlike humans, these creatures don’t have a way to escape the heat, so they are often affected even worse.

  • Crop damage. Many crops aren’t designed to handle high heat, or they may require extra water. Heat causes crops to become stressed, limiting yields. Plus, droughts can also come with heat waves, limiting a farmer’s options. Heat may also increase the risk of pests and diseases.
  • Harm to wildlife. Extreme amounts of heat also harm wildlife. Heat may make it harder for them to find food, stay hydrated, or breed. It may even alter whole breeding cycles and migrations.
  • Degradation of ecosystems. Heat affects different organisms differently. Some don’t mind the heat, while others do. Either way, heat will decrease the diversity in an ecosystem, affecting the whole web. Habitat may be damaged and can take several years to bounce back.

What’s Next for San Bernadino County Residents?

Keep an eye on the news for extreme heat warnings.

©Wirestock Creators/

Residents of San Bernardino County can take several steps to protect themselves and those around them.

You should always stay informed on local weather events and warnings, which will help you avoid excessive activities during heat waves. Sign up for emergency notifications and check the weather before heading outside. You can’t react to a heat wave if you don’t know when there will be a heat wave.

Before a heat wave strikes, make a plan for you and your family. Have emergency equipment, such as cooling packs, and know the signs of heat-related illnesses. If anyone in your family has chronic conditions, plan a way to continue treatment even during a heat wave, if necessary.

You should build an emergency kit with all the essentials to survive a heat wave, including water, food, medications, and first aid kits. It helps to keep an emergency kit in your car, as well. You never know when you’ll need to combat extreme heat.

While you still can, take action to reduce the harm from a heat wave. Install a cooling roof, for instance, and make sure your HVAC is properly maintained. Ensure you have working fire extinguishers and smoke detectors.

The photo featured at the top of this post is © Ed Connor/

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About the Author

Kristin is a writer at A-Z Animals primarily covering dogs, cats, fish, and other pets. She has been an animal writer for seven years, writing for top publications on everything from chinchilla cancer to the rise of designer dogs. She currently lives in Tennessee with her cat, dogs, and two children. When she isn't writing about pets, she enjoys hiking and crocheting.

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