Arizona Faces Early Heat Wave, Doctors Warn of Increased Illness Risks

Valleywise Health physicians urge caution as temperatures could reach record highs in the Valley starting this week.

Mar. 11, 2026 at 9:49pm

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Arizona is bracing for an early heat wave with the potential for record-breaking temperatures, prompting warnings from Valleywise Health doctors about the increased risks of heat-related illnesses. The forecast calls for several days of record- or near-record-breaking heat in the Phoenix area starting on Thursday, with the possibility of reaching triple digits as early as March 17 - the earliest 100-degree day on record.

Why it matters

Early season heat waves can be more dangerous because people's bodies haven't had enough time to adjust to the high temperatures, raising the risk of heat stress and heat stroke. This is especially concerning for out-of-town visitors who are not acclimatized to the Arizona heat.

The details

Emergency medicine physicians at Valleywise Health are urging residents and visitors to be cautious during the upcoming heat wave. They warn that the body's physiological response may not be ready to ramp up and respond to the extreme temperatures, increasing the chances of early heat illness.

  • The forecast high on March 17 could reach triple digits.
  • If temperatures top 100 degrees, it would be the earliest triple-digit day on record, breaking the previous record set on March 26, 1988.

The players

Valleywise Health

A healthcare system in Arizona that is issuing warnings about the upcoming heat wave and increased risks of heat-related illnesses.

Dr. Paul Pugsley

An emergency medicine physician at Valleywise Health Medical Center who is cautioning about the dangers of the early heat wave, especially for out-of-town visitors.

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What they’re saying

“One of our concerns with early spikes in outdoor temperatures is that our out-of-town visitors are not acclimatized to the heat. Their bodies aren't physiologically ready to ramp up and respond, and they might not recognize the signs of early heat illness.”

— Dr. Paul Pugsley, Emergency Medicine Physician, Valleywise Health Medical Center

The takeaway

This early heat wave in Arizona highlights the importance of being prepared for extreme temperatures, especially for those who are not used to the state's climate. Residents and visitors should take precautions to stay hydrated, limit time outdoors, and be aware of the signs of heat-related illnesses.