Medically reviewed by Pankajavalli Ramakrishnan, MD, PhD

While we often associate heart attacks with winter’s cold snap, research reveals a more subtle pattern with strokes: a modest increase during cooler months. As we head into fall and winter, understanding this seasonal trend—and more importantly, stroke prevention—becomes increasingly relevant.

The Science Behind Seasonal Strokes

Research has documented measurable connections between colder weather and stroke occurrence. A comprehensive analysis of nearly 172,000 stroke hospitalizations across the United States found that these events happened more frequently during periods of colder average temperatures and significant temperature fluctuations. Similarly, German researchers discovered that rapid temperature drops—specifically every 2.9°C (5.2 °F) decrease within 24 hours—corresponded with an 11 percent rise in stroke incidence, with even higher rates among those already at elevated risk.

Why Cold Weather May Play a Role

Several physiological changes during cooler weather may contribute to this pattern. Cold temperatures can cause blood vessels to constrict, potentially raising blood pressure in susceptible individuals. Additionally, blood tends to become slightly thicker in cold conditions, which may affect circulation. Seasonal changes in activity levels, vitamin D exposure and even respiratory infections common in fall and winter may also play supporting roles.

Putting Risk in Perspective

It’s important to understand that weather is just one small piece of the stroke puzzle. Your fundamental risk factors, including high blood pressure, diabetes, smoking, atrial fibrillation and family history, matter far more than the thermometer reading. A person with well-controlled risk factors faces minimal additional concern from seasonal changes.

Prevention Remains Key

Focus on proven prevention strategies: 

• Maintain regular blood pressure monitoring
• Take prescribed medications consistently
• Stay physically active year-round
• Manage chronic conditions effectively

If you’re at higher stroke risk, work with your healthcare provider to optimize your prevention plan before winter arrives.

Know the Signs

Regardless of season, recognize stroke warning signs using BE FAST: 

• Balance: sudden loss of balance or coordination
• Eyes: sudden vision changes in one or both eyes
• Face: facial drooping on one side
• Arms: weakness in one arm
• Speech: slurred or hard-to-understand speech
• Time: call 9-1-1 immediately

While cooler weather may contribute to a small seasonal increase in strokes, this shouldn’t cause alarm. Focus on the factors you can control and know when to seek emergency care. If you’re at higher risk for stroke or want to discuss prevention strategies, WMCHealth’s neurology specialists are here to help. To learn more or schedule a consultation, visit our website or call 914-592-2400.