Updated: August 15, 2026

COVID-19 activity is showing signs of a summer increase in parts of the United States, particularly in the West and South.

Summer COVID Surge in United States Explained

The summer COVID surge in the United States is attracting renewed attention as infections show signs of increasing across parts of the country in August 2026. California and several other Western and Southern states are seeing evidence of rising transmission, while wastewater monitoring is providing an early signal that COVID-19 activity is increasing in some communities.

The increase does not currently resemble the enormous waves seen during the early years of the pandemic. However, the latest data suggest that COVID-19 continues to follow a seasonal pattern in which activity can rise during the summer as well as during winter. The Centers for Disease Control and Prevention has warned that larger summer increases remain possible depending on how the virus evolves.

Is There a Summer COVID Surge in the U.S.?

There are signs of a summer COVID increase, although describing the situation as a nationwide severe surge requires some caution. Recent CDC estimates cited in current reporting show COVID infections growing or likely growing in many states, while overall emergency-department activity remains relatively low.

California has become one of the clearest examples. Recent reporting found that COVID-19 was increasing in California and across portions of the West and South, including Texas, Florida, Missouri, Alabama, Oregon, Utah, Nevada, New Mexico and Hawaii. The CDC still characterized emergency-department levels as very low, meaning rising transmission has not yet translated into a large nationwide wave of severe disease.

Where Is COVID Rising Most?

The pattern is uneven across the United States. Some Western and Southern states are seeing increases, while other areas remain comparatively quiet.

California has drawn particular attention because wastewater levels in several communities have risen substantially. Recent Bay Area reporting described high or increasing virus levels in places including San Francisco, Palo Alto and San Jose, while some other communities remained at lower levels.

This geographic variation is important. A summer increase in one region does not necessarily mean every part of the country is experiencing the same level of transmission at the same time.

What Does the CDC Say About the Summer Wave?

The CDC's summer outlook anticipated that COVID-19 activity could increase during the warmer months. In its July assessment, the agency said COVID activity was low in most of the country but noted that larger summer increases remained possible, especially if a variant capable of evading existing immunity became more common.

The CDC also projected that regions with relatively little COVID activity during the preceding winter could experience greater summer increases.

This means a summer wave is not unexpected. COVID-19 has increasingly behaved as a year-round respiratory virus with recurring seasonal peaks rather than following the simple winter-only pattern familiar from influenza.

Why Does COVID Rise in Summer?

COVID-19 can spread during every season, but several factors can encourage transmission during summer. People travel more, attend large indoor events and move through crowded airports and public spaces. Extremely hot weather can also drive people indoors into air-conditioned environments.

School and university schedules can matter as well. As students return to classrooms and campuses, more people mix closely with others from different communities, potentially accelerating local transmission.

These factors do not operate independently. The timing and intensity of a summer wave also depend on the amount of immunity in the population and the characteristics of currently circulating SARS-CoV-2 variants.

What Are Wastewater Levels Showing?

Wastewater surveillance has become one of the most useful tools for detecting changes in COVID activity because it can identify viral material in sewage before many infections appear in traditional clinical data.

The CDC explains that wastewater monitoring can detect SARS-CoV-2 in communities even when infected people do not seek medical care or have symptoms. The agency updates national wastewater data weekly and uses categories ranging from very low to very high viral activity.

Recent reporting has highlighted elevated wastewater levels in parts of California. That is one reason public-health experts are watching the late-summer trend closely even though national emergency-department indicators remain relatively low.

Are COVID Hospitalizations Rising?

Hospitalizations are a more direct measure of severe disease than wastewater, but they generally lag behind early transmission indicators.

Available CDC surveillance has shown that COVID-19 currently causes far fewer severe cases than during the major pandemic waves. The agency's recent respiratory-virus data describe COVID activity as low in most areas, with emergency-department activity also remaining very low in the latest nationwide snapshot.

That does not mean severe cases have disappeared. Older adults and people with certain medical conditions remain at higher risk of complications, hospitalization and death when infected.

Which COVID Variant Is Driving the Summer Surge?

Current reporting has focused on the XFG-related lineage often referred to as “Stratus”. It is an Omicron-descended virus that has been detected in the United States and elsewhere.

Experts have not established that this lineage causes more severe disease than previous circulating variants. The bigger concern is how efficiently a variant spreads in a population with declining immunity from previous infection or vaccination.

Because variant proportions can change quickly, readers should rely on updated CDC surveillance rather than assuming that one strain will remain dominant throughout the summer.

Is the 2026 Summer Surge Worse Than Previous Years?

It is too early to make a definitive national comparison with every previous summer. However, the current pattern is consistent with a broader shift in COVID seasonality.

CDC analysis of the 2025-26 respiratory season found that the summer 2025 COVID wave actually produced a higher hospitalization peak than the winter peak that followed. The summer 2025 hospitalization peak was approximately 2.6 per 100,000 people during the week ending September 6, compared with about 2.0 per 100,000 during the winter peak.

That history helps explain why health officials are paying close attention to the 2026 summer increase.

Who Is Most at Risk?

Although COVID-19 is generally less severe than it was during the earliest pandemic years, serious illness remains possible.

Older adults, people with weakened immune systems, pregnant people and individuals with certain chronic medical conditions face greater risks of complications. Children under five, particularly very young infants, can also require additional attention when respiratory infections circulate widely.

The risk is therefore not distributed evenly across the population. A relatively small increase in overall infections can still matter greatly for vulnerable groups.

What Symptoms Should People Watch For?

COVID symptoms can vary from person to person and can overlap with influenza and other respiratory infections. Common symptoms can include sore throat, cough, congestion, fever, fatigue, headache and muscle aches.

Some people develop more serious symptoms, such as difficulty breathing or persistent chest discomfort. People with concerning symptoms should seek appropriate medical attention rather than relying on a home test alone.

What Should People Do During the Summer Surge?

People can take practical steps to reduce their chances of infection, particularly during periods of increased local transmission.

• Stay home when sick and avoid close contact with vulnerable people while symptomatic.
• Consider masking in crowded indoor settings when local COVID activity is high.
• Improve indoor ventilation when possible.
• Use a COVID test when symptoms or a recent exposure make infection plausible.
• Follow current vaccination guidance, especially if you are at higher risk of severe illness.

The appropriate level of precaution depends on a person's health, exposure risk and local transmission levels.

Should People Get a COVID Vaccine During the Summer?

Vaccination remains an important tool for reducing the risk of severe COVID-19, particularly among people at higher risk. CDC guidance has emphasized staying up to date with recommended COVID vaccination while continuing to monitor seasonal changes in circulation.

The timing of vaccination can depend on age, medical risk and previous doses, so people should check the latest CDC recommendations rather than assuming that the same schedule applies to everyone.

Could the Summer Surge Get Worse?

It could, but the eventual size of the wave is uncertain. The CDC has specifically noted that a larger summer increase could occur if a variant with substantial immune-escape characteristics becomes more common.

At the same time, current nationwide indicators do not show a return to the scale of the major pandemic waves. That makes the present situation better described as a seasonal increase under close observation rather than a new 2020-style emergency.

Why This Summer COVID Surge Matters

The most important change is that COVID-19 is no longer behaving like a simple winter respiratory illness. Historical U.S. surveillance shows recurring late-summer and winter peaks, while recent CDC analysis suggests that summer activity can sometimes exceed winter activity.

That seasonal pattern has practical consequences. Health systems, schools, workplaces and travelers may need to account for COVID activity during summer just as they have traditionally done during winter respiratory-virus season.

Bottom Line

The summer COVID surge in the United States is real in the sense that multiple indicators show increasing activity in parts of the country, particularly in portions of the West and South. California has emerged as one of the clearest areas of concern, with wastewater data and other indicators suggesting that infections are increasing.

However, the latest available national CDC information still describes overall COVID activity as low in most areas, and emergency-department activity remains very low.

The situation is therefore best understood as a developing seasonal increase rather than a nationwide crisis. Wastewater surveillance, hospitalizations and emergency-department trends will be especially important in determining whether the 2026 summer wave continues to build through August and September.