and humid, with a daily mean temperature of in July. Nighttime conditions are often exacerbated by the urban heat island phenomenon, while daytime temperatures exceed on average of 17 days each summer and in some years exceed . Extreme temperatures have ranged from , recorded on February 9, 1934, up to on July 9, 1936. Summer evening temperatures are elevated by the urban heat island effect, which causes heat absorbed during the day to be radiated back at night, raising temperatures by as much as when winds are slow. Manhattan receives of precipitation annually, which is relatively evenly spread throughout the year. Average winter snowfall between 1981 and 2010 has been ; this varies considerably from year to year. Governors Island in New York Harbor is planned to host a US$1 billion research and education center with the intention of making New York City the global leader in addressing the climate crisis. Boroughscape Demographics In 2020, 1,694,251 people lived in Manhattan. At the 2010 U.S. census, there were 1,585,873 people living in Manhattan, an increase of 3.2% since 2000. Since 2010, Manhattan's population was estimated by the U.S. Census Bureau to have increased 2.7% to 1,628,706 , representing 19.5% of New York City's population of 8,336,817 and 8.4% of New York State's population of 19,745,289. As of the 2020 U.S. Census, the population density of New York County was , the highest population density of any county in the United States. In 1910, at the height of European immigration to New York, Manhattan's population density reached a peak of 101,548 people per square mile (39,208/km²). Manhattan is one of the highest-income places in the United States with a population greater than one million. , Manhattan's cost of living was the highest in the United States. Manhattan is also the United States county with the highest per capita income, being the sole county whose per capita income exceeded $100,000 in 2010. However, from 2011–2015 Census data of New York County, the per capita income was recorded in 2015 dollars as $64,993, with the median household income at $72,871, and poverty at 17.6%. In 2012, The New York Times reported that inequality was higher than in most developing countries, stating, "The wealthiest fifth of Manhattanites made more than 40 times what the lowest fifth reported, a widening gap (it was 38 times, the year before) surpassed by only a few developing countries".