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periods of very hot conditions. In July, there were. 10 days with high temperatures of 90 degrees or more, which is close to two times greater than the normal for ...
CUSP

Climate Newsletter THIS PAST SUMMER IN NEW YORK CITY

A seasonal review of weather, climate and community from the Climate & Urban Systems Partnership (CUSP)

Temperatures If you had to guess, would you say temperatures were above, near, or below normal this summer? Believe it or not, temperatures in New York were just slightly above normal. While the summer overall has been quite seasonable, there have been periods of very hot conditions. In July, there were 10 days with high temperatures of 90 degrees or more, which is close to two times greater than the normal for the month. During periods of hot weather, greater demand is placed on the energy companies to provide enough electricity for the extra cooling needed, so don’t be surprised if your July utilities bill was high.

Precipitation The summer in New York started out quite wet, with June 2013 going down as the 2nd wettest June on record. Of all the rain that fell in June, approximately 45% fell over just 2 days, the 7th and 8th. If you feel that when it’s raining it seems to be coming down harder, you aren’t alone -- scientists have observed an overall trend towards more heavy precipitation events in the Northeast. This June certainly illustrates the expression, “when it rains, it pours.” July, however, had less rainfall and was drier than average. With average conditions in August, the summer overall had more rain than a normal year. Even if there are more days with heavy precipitation, it doesn’t always mean you’ll have to water your lawn and garden less. Many lawns in the New York City area are still brown even with the wet June. This is because when it rains very hard over a short period of time, most of the water cannot be absorbed into the ground, and the excess water runs straight into water bodies. Using a rain barrel or other water catchment system is one strategy for storing and utilizing extra rainfall from heavy precipitation events.

Comparing the last 3 summers

Summer 2011 17 days with high ABOVE 90o

8 days with LOW ABOVE 70o

7 days WITH 1” or more rainfall

Summer 2012 18 days with high ABOVE 90o

6 days with LOW ABOVE 70o

2 days WITH 1” or more rainfall

Summer 2013 14 days with high ABOVE 90o

14 days with LOW ABOVE 70o

3 days WITH 1” or more rainfall

NEW YORK CITY’S SUMMER: 2013

WHAT DOES IT MEAN FOR US? Heat is generally the leading weather-related cause of death in the United States every year. Extremely hot weather increases the risk of respiratory and cardiovascular diseases, as well as dehydration and mental health concerns. Cities may be especially at risk due to the urban heat island effect. This phenomenon is the tendency for cities to be hotter than surrounding areas due to the greater amount of concrete and dark surfaces in cities, which absorb more heat from the sun than the trees and light surfaces that are more common outside of cities. If you commute to or from the city, you may be able to feel the temperature difference between the most urban and dense portions of the city, the outer boroughs, and the suburban areas. As climate change is likely to cause warmer temperatures and more heat waves, scientists project that heat-related illness and deaths are also likely to increase. A recent study for New York found that heat-related deaths might increase by 20% by the 2020s and up to 90% by the 2080s. These numbers, however, are dependent on the steps taken in the mean time to slow climate change effects by lowering greenhouse gas emissions, among other strategies. NYC is already taking steps to reduce the impact of heat on health, including the creation of a heat warning system, opening of public cooling centers, and increasing green space and reflective roofs to decrease the city’s urban heat island effect.

The city is improving the energy efficiency of key sectors, including transportation.

HOW DO WE RESPOND? City planners and decision makers in New York City are taking steps to reduce the impacts of future climate change. These steps include actions designed to lower the amount of gases emitted into the atmosphere that contribute to climate change. One such action the city is taking is the improvement of energy efficiency, meaning less power usage in key city sectors such as buildings and transportation. Also, to prepare for the higher temperatures expected with future climate changes, the city has prepared a heat alert system to provide warnings to residents at greatest risk during heat waves.

A community garden in Brooklyn. This type of green space helps reduce the city’s urban heat island effect.

NEW YORK CITY’S SUMMER: 2013

Heat Waves

Weather vs. Climate

90o The most intense heat wave in New York City this summer occurred in mid July, with 6 consecutive days with high temperatures at or above 90 degrees. There was a shorter heat wave at the start of July, only lasting 3 days. Neither June or August had a heat wave. Prolonged periods of heat can greatly impact the transportation system in New York City. Materials used in roadways and railroad tracks can break down and buckle when temperatures are very hot, causing service disruptions. Interruptions to the electric supply caused by high temperatures can also delay train and subway service. When building new roads and rails, materials that can withstand higher temperatures should be used.

Climate scientists project that the number of hot days each year is very likely to increase over the course of the 21st century. In New York, 90 degree days are projected to increase from 18 to as many as 31 days per year by the 2020s due to climate change.

This project was supported, in part by the National Science Foundation.

One saying often used to describe the difference between weather and climate is, “climate is what you expect, weather is what you get.” Weather and climate differ by the time scales that define them; climate is the average of weather conditions over a long period of time. For example, summer in New York is usually warm, with an average high temperature in July of 84 degrees. That is the climate - the average of many years’ weather, with some years having hotter temperatures and some having colder. The weather, then, is the conditions in a particular area at a particular time. For example, the high temperature on July 28th in New York was 78 degrees, which is cooler weather than you might expect given the normally hot climate.

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