Opioid Crisis: Does Cold Weather Increase the Risk of Fatal Overdose?

Opioid epidemic, drug abuse concept with closeup on two heroin syringes or other narcotics surrounded by scattered prescription opioids. Oxycodone is the generic name for a range of opioid painkillers
For as much as we know about the dangers of opioids, relatively little is known about how environmental factors might influence opioid-related mortality. Does cold weather increase the risk of fatal overdose?

Much has been written about the opioid epidemic in the United States. Yet, for as much as we know about the dangers of opioids, relatively little is known about how environmental factors might influence opioid-related mortality.

“It is well known that opioids induce respiratory depression, and that’s what causes a fatal overdose,” said Brandon Marshall, an associate professor of epidemiology at Brown University’s School of Public Health. “However, there may be a host of other risk factors that contribute to opioid overdose deaths, which could be avenues for effective interventions.”1

Link Found Between Weather and Opioid Overdose Deaths

A team of researchers led by Marshall found that opioid overdoses are more likely to occur in the days after cold snaps than on days when temperatures are mild. Their findings were published in Epidemiology.2

The researchers examined 3275 opioid overdose deaths in Connecticut and Rhode Island between 2014 and 2017. They compared the mean temperature on the day of death and up to 2 weeks prior with the mean temperature of 3 reference days in the same month. They found that an average temperature of 32°F 3 to 7 days before death was associated with a 25% increase in the risk of fatal overdose compared with periods with an average temperature of 52°F.

Interestingly, despite an increase in overdoses in the days following cold snaps, the investigators did not identify a direct link between colder temperatures on the day of death and the risk of fatal overdose. They posited that this might have to do with uncertainty about when people died or cumulative effects of low temperatures.1

Explaining the Link

The researchers offered a few theories to explain why cold snaps might contribute to an increase in opioid overdose deaths. One possibility is that cold weather alters behavior. People might be more likely to use opioids alone when the weather is cold, leaving them susceptible to fatal overdose in the event no one is present who can administer naloxone.1

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Another theory is that cold weather might affect the opioid distribution network. This would increase the likelihood of people using drugs that contain illicit fentanyl or that are more potent than they’re accustomed to.

A third possibility is that opioid use in cold weather might result in negative biological effects. Opioids reduce breathing rates, which can be especially problematic in low temperatures. In addition, some opioids may make it more difficult to regulate body temperature.

Reducing Risk

Most fatal overdoses that occurred during the study took place indoors, suggesting that offering support for home heating costs or providing warm locations for people to go during cold snaps might help prevent opioid overdose deaths.1

Moving forward, the researchers would like to examine whether major storms increase the risk of fatal overdose.


  1. Cold weather increases the risk of fatal opioid overdoses, study finds. Brown University. June 17, 2019. Accessed June 19, 2019.
  2. Goedel WC, Marshall BDL, Spangler KR, et al. Increased risk of opioid overdose death following cold weather [published online June 6, 2019]. J Epidemiol. 2019. doi: 10.1097/EDE.0000000000001041