NYC’s Overnight Temps to Interfere with Summer Shuteye Unequally

A look at how sleep-related problems could intensify in the city that never sleeps.

Rising nighttime temperatures, due to climate change, point to more lost sleep for New Yorkers this summer and in the future. Increased nighttime temperatures shorten sleep primarily through delayed onset, increasing the probability of insufficient sleep, according to new research.

In every New York City borough there are neighborhoods that face a higher risk of heat-related issues, according to the NYC Health Department’s Heat Vulnerability Index, but the thread connecting them all is that they have more residents in low-income neighborhoods, which tend to be disproportionately Black and immigrant in composition. About 91% of New Yorkers have air conditioning, and the lack of home air conditioning is an important risk factor for heat-related stress.

Based on the National Oceanic and Atmospheric Administration’s (NOAA) forecast for July, August, and September, New York faces a 50% to 60% chance of a hotter-than-normal mid-summer through early fall.

According to Gro Intelligence NOAA CPC data, the July 16-21 period is traditionally the hottest stretch of daily high temperatures in Manhattan each summer.

Typically, elevated nighttime highs follow higher daytime temperatures, and that could intensify sleep-related nighttime temperature problems in places like New York City, the US city with the third most intense urban heat island effect. Most doctors recommend keeping the thermostat set between 60-67°F degrees for the most comfortable sleep.

Currently, New York City’s minimum summertime temperatures, which usually occur overnight, have a 30-year average of around 68°F. But, by 2100, New York City’s minimum temperatures will climb to a summertime average in the mid-70s, under scenario SSP3-7.0, the higher of the two Intergovernmental Panel on Climate Change (IPCC) “middle of the road” emissions scenarios.

Minimum temperatures tend to occur at night. The chart above shows minimum temperatures for Manhattan out to 2100. The IPCC's trajectory estimate for global warming falls between SSP 2-4.5 and SSP 3-70. The blue line, SSP 5-8.5, is the IPCC's highest emissions scenario.

This would put Manhattan’s nighttime temperature in 2100 near Houston’s current 30-year average minimum summertime temperature. (Houston, by comparison, is projected to see its minimum summertime temperatures soar into the low to mid-80s by the end of this century, under the IPCC’s SSP 2-4.5 and SSP 3-7.0 climate change scenarios.)

Houston in Harris County, Texas is one of the US’ hottest cities. The chart above shows minimum temperatures for Harris County through 2100. The IPCC's trajectory estimate for global warming falls between SSP 2-4.5 and SSP 3-70. The blue line, SSP 5-8.5, is the IPCC's highest emissions scenario.

In May, the New York State Public Service Commission said that the state’s electric grid and its electric utilities are prepared for increased summer demand for electricity, but it also said that the statewide price for electricity paid by full-service residential customers on average is expected to be about 12% higher than a year ago, depending on demand, weather conditions, and a customer’s location in the state.

As air conditioning is the best defense against heat and with New Yorkers’ budgets tightening on rising inflation, many city residents could be facing more sleepless nights as ambient temperatures rise.