New York Weather

The climate of New York state is generally humid continental, while the extreme southeastern portion of the state (New York City and Long Island area) lies in the warmer humid subtropical climate zone. Winter temperatures average below freezing during January and February in much of the state of New York, but several degrees above freezing along the Atlantic coastline, including New York City.

Seasonally, summer-like conditions prevail from June to early September statewide, while areas in far southern New York and New York City have summer conditions from late May through early-mid October. Cold-air damming east of the Appalachians leads to protracted periods of cloud cover and precipitation east of the range, primarily between the October and April months. Winter-like conditions prevail from November through April in northern New York, and from December through March in southern New York. On average, western New York is much cloudier than points south and east in New York, much of it generated from the Great Lakes.

Annual precipitation is fairly even throughout the year across the state of New York. The Great Lakes region of New York sees the highest annual rain and snow amounts in the state of New York, and heavy lake-effect snow is common in both western and central New York in winter. In the hotter months, large, long-lived complexes of thunderstorms can invade the state from Canada and the Great Lakes, while tropical cyclones can bring rains and winds from the southwest during the summer and fall. Hurricane impacts on the state occur once every 18–19 years, with major hurricane impacts every 70–74 years. An average of ten tornadoes touch down in New York annually.

The annual average temperature across the state ranges from around 39 °F over the Adirondack Mountains to near 53 °F across the Hudson Valley and Long Island, to around 56 °F within New York City. Weather in New York is heavily influenced by two air masses: a warm, humid one from the southwest and a cold, dry one from the northwest. A cool, humid northeast airflow from the North Atlantic is much less common, and results in a persistent cloud deck with associated precipitation which linger across the region for prolonged periods of time. Temperature differences between the warmer coast and far northern inland sections can exceed 36 degrees Fahrenheit, with rain near the coast and frozen precipitation, such as sleet and freezing rain, falling inland. Two-thirds of such events occur between November and April.

Summer

Summers in New York State significantly vary by region. The summer climate is cooler in the Adirondacks due to higher elevation. The Adirondacks typically experience pleasant dry weather in the summer, with temperatures in the range of 66 °F–73 °F. Evenings in the Adirondacks are chilly, with temperatures ranging on average between 45 °F–54 °F. Most of Western New York, Central New York, the mid-Hudson Valley and the Catskills have moderate temperatures but are usually humid, with temperatures ranging 80 °F–85 °F.

Nights in central New York state are often muggy, between 61 °F–67 °F. The New York City area and the Lower Hudson Valley in contrast feature more sultry and tropical summers with frequent bouts of high temperatures and high dew points. Temperatures in this area are usually between 86 °F–91 °F but slightly cooler by the ocean and south-facing shorelines of Long Island and the temperatures there are between 85–90 °F. Nights are warm and muggy, between 68–75 °F.

Heat waves

Heat waves are common in New York State which bring high heat and humidity. Heat waves occurs at least two times each summer and are an average of 3–5 days. Only the Adirondacks does not see oppressive temperatures during most heat waves in New York State. The Adirondacks have warm to hot temperatures with some humidity during a heat wave but it is typically cooler than the rest of the state during a heat wave.

Winter

Winter temps vary just like the summer temperatures. The Adirondacks are the coldest in New York and are almost always below freezing for almost 3 straight months. The temps are between 18–23 °F. Nights are cold and frigid, between −2 and 4 °F. Most of Central New York, Mid Hudson Valley, and the Catskills have moderate temperatures that are not very cold but not mild, Between 30–35 °F. Nights are cold but not frigid, between 18–23 °F. New York City, Hudson Valley, and Long Island are the warmest in New York State because of warmer ocean temperatures which keep these area between 37–42 °F, warmer than locations upstate. Downstate nights typically range between 27–31 °F.

Winter snowfall

Snowfall in New York State also significantly varies by region. Lake-effect snow takes place in Western New York and the Adirondacks with Lake Ontario and Lake Erie. Lake-effect snow is very localized and areas may see feet of snow while others see only an inch or none at all. The Adirondacks see the most snowfall because of lake-effect snowfall and higher elevations which see between 100–200 inches per year and some may see more than 200 inches per year, especially western parts of the Adirondacks.

Western and Central New York see between 75–150 inches per year depending on location and where the bands hit. The Catskills see an average snowfall, between 25–50 inches and most of it is from nor-easters which are almost always snow. New York City, Long Island, and the Hudson Valley see the least amount of snowfall because they see warmer temperatures from the warmer ocean temperatures and the nor-easters there are mixed with rain, between 10–25 inches.

Blizzards

The blizzards that ravage New York and harry travelers on the mountain pass are savage. A blizzard in New York typically lasts 2d4 hours, and whenever the characters are caught in one, the following rules apply until it ends.

A blizzard’s howling wind limits hearing to a range of 100 feet and imposes disadvantage on ranged weapon attack rolls. It also imposes disadvantage on Wisdom (Perception) checks that rely on hearing. The wind extinguishes open flames, disperses fog, erases tracks in the snow, and makes flying by nonmagical means nearly impossible. A creature falls at the end of its turn if it is flying by nonmagical means and can’t hover.

Visibility in a blizzard is reduced to 30 feet. Creatures without goggles or other eye protection have disadvantage on Wisdom (Perception) checks that rely on sight due to blowing snow.

Any creature that is concentrating on a spell in a blizzard must succeed on a DC 10 Constitution saving throw at the end of its turn or lose its concentration on the spell unless the creature is sheltered against the elements (for example, in a tent).

Veering Off Course.

It’s easy to veer off course while traveling through a blizzard, and it’s also easy for party members to become separated from one another, which is why the wisest course of action is to stay put and wait for the blizzard to pass.

If the characters travel during a blizzard, have the players designate one party member as the navigator. At the end of each hour of travel through the blizzard, the DM makes a DC 15 Wisdom (Survival) check on behalf of the navigator. On a successful check, the party stays on course. On a failed check, the party wanders off course, putting its members no closer to their destination than they were at the start of that hour. If the check fails by 5 or more and the party members aren’t tied together, one randomly determined party member becomes lost in the blizzard and separated from the others. If the group tries to reunite with its missing member, have the party members (including the missing one) make a DC 15 Wisdom (Survival) group check at the end of each hour. If this group check succeeds, the missing party member is found, but no progress is made toward reaching the group’s intended destination that hour. The group check can be repeated after each hour spent searching for the missing party member.

Extreme Cold

A creature exposed to the cold must succeed on a DC 10 Constitution saving throw at the end of each hour or gain one level of exhaustion. Creatures with resistance or immunity to cold damage automatically succeed on the saving throw, as do creatures wearing cold weather clothing (thick coats, gloves, and the like) and creatures naturally adapted to cold climates, such as reindeer and snowy owlbears.

Temperatures.

New York can claim the coldest temperature ever recorded in the region, with an all-time record low of negative 52 degrees. The average temperature is much warmer at 26F during January. Wind chill can lower these temperatures greatly.

Frigid Water

A creature can be immersed in frigid water for a number of minutes equal to its Constitution score before suffering any ill effects. Each additional minute spent in frigid water requires the creature to succeed on a DC 10 Constitution saving throw or gain one level of exhaustion. Creatures with resistance or immunity to cold damage automatically succeed on the saving throw, as do creatures that are naturally adapted to living in ice-cold water.

Winter Overland Travel

The fastest way to travel across the winter landscape is by dogsled. But dogs are expensive and require food, water, and shelter. Unless they have more equipment than they can carry, adventurers are better off traveling on foot. The speed that characters can travel across the winter landscape is given in the Overland Travel table. Travel is less time-consuming on the snowy roads and trails that connect the settlements of New York.

Dogsleds

An empty sled costs 20 credits, weighs 300 pounds, and has room at the back for one driver. A sled dog (use the wolf stat block in appendix A of the Monster Manual) costs 50 credits and can pull 360 pounds. Sled dogs must take a short rest after pulling a sled for 1 hour; otherwise, they gain one level of exhaustion.