NYC Monthly Summary: August 2015

It was hot in New York City this August. Everyday produced a high temperature above 80°F and eight days saw the mercury climb to 90°F or higher, which is twice the average number for August. Additionally, the month brought the city its first official heat wave in two years. With overnight lows also running mostly above normal, the city’s mean temperature for the month was 79°F, which is 3.8°F above average. This makes August 2015 the city’s 3rd warmest August on record.

On the precipitation side of things, August was very dry in the Big Apple. All told, the city received a mere 2.35 inches of rain in Central Park, which is 2.09 inches below average. On the latest report (8/25) from the US Drought Monitor, the NYC area is listed as “abnormally dry”.

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First Heat Wave in NYC Since 2013

It’s official! We’re having a heat wave in New York City.

While we have hit the 90°F mark a few times already this summer, this is the first real heat wave of the season. Actually, it is the first official heat wave in the Big Apple since 2013.

The threshold for what constitutes a heat wave varies by region, but here in the NYC area it is defined as three consecutive days with temperatures reaching 90°F or higher. In Central Park, the temperature reached 92°F on Saturday, 93°F on Sunday, and today it climbed to 95°F – tying the record high for the date.

When factoring in the high levels of humidity these past few days, the heat index felt like it was near 100°F. While these conditions are oppressive, they can also be dangerous. Both a heat advisory and air quality alerts were issued for the city.

For most of the summer, temperatures have been running slightly above average in NYC, but it is interesting to note that there has not been much extreme heat. To date, we have only had ten days with readings at or above 90°F. On average, we typically see fifteen for the season.

NYC Monthly Summary: July 2015

July is normally the warmest month on the calendar for New York City, and this year was no exception. Despite getting off to a relatively cool start, the month brought us five days with temperatures in the 90s. These hot days helped bring the city’s mean temperature for the month up to 78.8°F, which is 2.3°F above average.

While we had a few stretches of very warm and humid days, including some where the heat index reached  the triple digits, it is interesting to note that we did not technically have a single heat wave all month. In this part of the US, a heat wave is defined as three consecutive days with temperatures reaching 90°F or higher.

On the precipitation side of things, NYC was mostly dry. In all, we received 3.98 inches of rain in Central Park, which is 0.62 inches below average. Of this total, 1.95 inches fell in a single day as a cold front moved through the area triggering thunderstorms and intense downpours.  July is typically the wettest month of the year in the Big Apple.

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Exploring the Urban Heat Island Effect Within City Limits

During the summer months in New York City, you often hear people talking about plans to escape the city’s heat with trips to the beach or mountains. This is because NYC, like most large cities, is an urban heat island. With miles of paved surfaces that absorb heat, it is generally warmer than surrounding rural areas.

Within city limits, the temperature difference between an asphalt covered street and a nearby park lawn can demonstrate this phenomenon on a smaller scale. Below are some photos of measurements we made around midtown Manhattan at 2:30 PM this afternoon when the air temperature was 95°F.

On the street, the temperature was 122°F in the sun and 101°F in the shade. On the park lawn, only a few feet away, the temperature in the sun was 99°F and a relatively cool 85°F in the shade.  Hands down, the best place to beat the heat – even in the city – is on a grassy surface in the shade.  Stay cool!

Comparing temperatures of surfaces in sun and the shade around midtown Manhattan on July 29th.

Comparing temperatures of surfaces in the sun and the shade around midtown Manhattan on July 29th when the air temperature was 95°F .  Credit: The Weather Gamut.

NYC Monthly Summary: June 2015

June 2015 felt a bit like a weather rollercoaster in New York City. We had highs that ranged from an unseasonably cool 55°F to our first 90-degree day of the year.  In the end, however, the cold and warmth averaged each other out. The city’s mean temperature for the month was 71.2°F, which is only 0.2°F below normal.

On the precipitation side of things, the city had 14 days with measurable rainfall.  In all, we received 4.79 inches of rain, which is 0.38 inches above normal. Of this total, 1.41 inches fell in a heavy rain event during the last weekend of the month. June marked the first time since March that the city had above average monthly rainfall.

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NYC Monthly Summary: May 2015

May was unusually warm and dry in New York City this year.

With 26 out of 31 days posting above average highs, including 18 days with readings in the 80s, May felt more like summer than spring. Overnight lows were also well above average throughout most of the month. All together, the city’s mean temperature for the month was 68.5°F, which is 6.1°F above average.  That makes May 2015 the city’s 3rd warmest May on record.

In terms of precipitation, May was exceptionally dry. Coming on the heels of a parched April, the city, according to the latest report (5/28) from the US Drought Monitor, is currently in a state of moderate drought. All told, the city received a mere 1.86 inches of rain in Central Park. Of this meager total, 1.46 inches fell in a single day – the last day of the month – and caused localized flash floods. May, on average, typically brings NYC 4.19 inches of rain.

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

An Early Taste of Summer for NYC

The official start of summer is more than a month away, but temperatures have been soaring in New York City!

A large ridge in the jet stream has ushered unseasonably warm air into the region. In fact, eight of the last twelve days have seen temperatures reach well into the 80s. Today, the mercury soared to 86°F in Central Park, making it the warmest day of the year to date. Our normal high for this time of year is 70°F.

While the pre-season warmth can be easy to acclimate to, especially after a cold and snowy winter, these summer-like conditions are not expected to last much longer. A cold front is forecast to move through the region late tonight sending temperatures back to more seasonable levels.

NYC Monthly Summary: April 2015

Transitioning to spring, April 2015 felt like a weather rollercoaster in New York City. We had highs that ranged from a chilly 43°F to a balmy 80°F.  In the end, though, the warmth won out. The city’s mean temperature for the month was 54.3°F, which is 1.3°F above normal. That makes April the first month since December to produce an above average temperature in the Big Apple.

In terms of precipitation, April’s famous showers were scarce this year. The city received a mere 2.08 inches of rain in Central Park. Of this meager total, 1.37 inches fell in a single day. On average, NYC typically gets 4.5 inches of rain during the month of April.

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

Spring has Arrived in NYC

After a cold and snowy winter, birds are chirping and flowers are starting to bloom in New York City. More than three weeks after the vernal equinox, spring has finally sprung!

With a high temperature of 72°F in Central Park, today was the warmest day the city has seen all year.  It has not been this warm in the Big Apple since October. Our normal high for this time of year is 61°F.

Spring Flowers in NYC Garden

Spring Flowers in NYC Garden.  Credit: The Weather Gamut

Similar Weather for Easter and Christmas in NYC

Easter and Christmas are major holidays associated with the beginning of two different seasons – spring and winter, respectively. Nonetheless, the weather conditions for their most recent occurrences in New York City were oddly similar.

The high temperature in Central Park yesterday, Easter Sunday, was 61°F and the low was 42°F.  Back on Christmas Day, December 25th, the high was 62°F and the low was 44°F, tying the record for the city’s third warmest Christmas. Conditions this Easter were only slightly above average for the date.

The warmest Easter on record for NYC, according to the local National Weather Service office, was in 1976 when the high temperature reached 96°F. The coldest was in 1940 when the high was only 31°F.