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Climate in Islandia · NOAA 1991–2020 normals

Neither notably warm, cold, wet nor dry, Islandia sits near the middle of U.S. towns

January mornings start at about 23°. Only 60° separates winter nights from summer afternoons. Its yearly precipitation tops that of 63% of U.S. towns. Central heating does most of its work from November to April, in months below 50° on average.

More snow than 64% of U.S. towns#708Snowiest  of 854 in NY
Milder January nights than 58% of U.S. towns#117Mildest winters  of 875 in NY
All NY rankings →

A year in Islandia at a glance

Each month’s typical high and low, and what it brings.

Jan40°23° 10" snow
Feb42°24° 9" snow
Mar49°31° 7" snow
Apr60°40° Last frost ~Apr 10
May69°49°
Jun79°59° 2 days 90°+
Jul84°65° 4 days 90°+
Aug82°64° 2 days 90°+
Sep75°57°
Oct65°46°
Nov now54°36° First frost ~Nov 2
Dec45°29° 5" snowWettest

What stands out about Islandia’s climate

Compared with towns across the U.S., with Islandia’s place in New York beside it.

A normal year

What a year in Islandia feels like

Typical highs and lows by season and by month, from NOAA’s 30-year normals.

Winter
42° / 26°
8 days with 1"+ of snow
Spring
59° / 40°
Last frost around Apr 10
Summer
82° / 63°
8 days reach 90°
Fall
65° / 46°
First frost around Nov 2
Best months to be outsideMayJunJulAugSepOctHighs of 62–84° and lows of 40° or more
Frost, heat & the growing season

About 207 frost-free days a year

In half of years the last 32° night comes by April 10 and the first by November 2. Frost and day counts come from NOAA’s station at Islip Li Macarthur Airport, 4 miles from the town’s center, at about the same height.

98
nights at or below 32° in a normal year
81st fewest of 875 in New York
Fewer freezing nights than 62% of U.S. towns
<1
nights at or below 0°
26th fewest of 875 in New York
Fewer nights at or below 0° than 69% of U.S. towns
8
days that reach 90°
445th fewest of 875 in New York
Fewer 90° days than 81% of U.S. towns
<1
days that reach 100°
722nd fewest of 875 in New York
Fewer 100° days than 56% of U.S. towns
7bUSDA zone
Plant hardiness zone 7b

The 2023 USDA map puts Islandia’s center in zone 7b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 6°. Plant labels use the zone; frost dates tell you when to plant.

Freezing nights by month

Average nights at or below 32°

25
JFMAMJJASOND

90° days by month

Average days at 90° or more

4.1
JFMAMJJASOND
Rain & snow

About 32 inches of snow a winter

Snow, measured at Islip Li Macarthur Airport, is heaviest from January through February, about 10 inches a month. Precipitation (rain plus melted snow) adds up to 46 inches a year; December is the wettest month and February the driest. Rain or snow falls on about 122 days a year.

46"
Rain + melted snow a year
235th wettest of 875 in New York
Wetter than 63% of U.S. towns
32"
Snow in a normal winter
708th snowiest of 854 in New York
More snow than 64% of U.S. towns
23 days
With 1"+ of snow on the ground
554th most of 653 in New York
More days with snow on the ground than 52% of U.S. towns

Rain + melted snow by month

Inches of water

4.5"
JFMAMJJASOND

Snowfall by month

Inches of snow

10"
JFMAMJJASOND
Heating & cooling

Heating and cooling a home in Islandia

85% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from November through April.

5,183 heating degree daysLess heating than 53% of U.S. towns
885 cooling degree daysLess cooling than 53% of U.S. towns

Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Islip Li Macarthur Airport.

Living here

Living with Islandia’s climate

What the numbers mean for a garden, a free afternoon and a bad-weather day.

The garden window

207 frost-free days in zone 7b. The last frost comes by Apr 10 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 2.

Get outside

Months with highs of 62–84° and lows of 40° or more: May, June, July, August, September and October. 4.8 miles of trails are waiting.

Parks & trails →
Storms and extremes

Of the yearly building losses FEMA expects in Islandia from natural hazards, river flooding is the largest share (59%); heat waves, cold waves, winter storms and ice storms together are 6%. Normals are averages; the hazards page covers the extremes.

Natural hazards →
Next door

Islandia and its neighbors

Every town next door is within a degree of Islandia in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.

North Great River: January low 25°, July high 83°Bohemia: January low 25°, July high 83°Brentwood: January low 24°, July high 84°Islip Terrace: January low 25°, July high 83°Nesconset: January low 24°, July high 83°Commack: January low 24°, July high 84°Smithtown: January low 25°, July high 83°Islip: January low 26°, July high 83°Lake Ronkonkoma: January low 23°, July high 84°Brookhaven: January low 23°, July high 83°Holbrook: January low 23°, July high 83°Central Islip: January low 25°, July high 83°Hauppauge: January low 23°, July high 84°Ronkonkoma: January low 23°, July high 84°Islandia: January low 23°, July high 84°IslandiaCentral IslipHauppaugeRonkonkoma
ColderMilder23° to 26°
Ronkonkoma23.2° about the same
Islandia23.4°
Hauppauge23.4° about the same
Central Islip24.5° +1.1°

Climates most like Islandia’s, farther away

TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.

TownJan. lowJuly highPrecip.Snow
Islandia, NY23°84°46"32"
Uniontown, PA22°84°45"28"
Manchester, MD22°84°47"34"
Fairmont, WV23°84°46"24"
Wilmington, OH21°84°44"27"

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.

Then and now

Warmer than it used to be

The last 30 years in Islandia averaged 2.3° warmer than the 1900s. The biggest change is in December (+3.7°).

+2.3°1991–2020 vs. 1901–2000

A bigger shift than in 98% of U.S. towns.

Winter+3.0°now 34°, was 31°
Spring+2.1°now 50°, was 48°
Summer+2.2°now 72°, was 70°
Fall+2.0°now 56°, was 54°

Change by month

JanFebMarAprMayJunJulAugSepOctNovDec

The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.

Compared with other towns

How Islandia compares

Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Islandia’s place among New York’s.

Summer heat84° July high
Cooler July afternoons than 62% of U.S. towns690th coolest of 875 in New York
Winter cold23° January low
Milder January nights than 58% of U.S. towns117th mildest of 875 in New York
Precipitation46" a year
Wetter than 63% of U.S. towns235th wettest of 875 in New York
Snow32" a winter
More snow than 64% of U.S. towns708th snowiest of 854 in New York
Hot days8 days at 90°+
Fewer 90° days than 81% of U.S. towns445th fewest of 875 in New York
Freezing nights98 a year
Fewer freezing nights than 62% of U.S. towns81st fewest of 875 in New York
Growing season207 frost-free days
A longer frost-free season than 72% of U.S. towns74th longest of 875 in New York
Month by month

Islandia weather by month

Highs, lows and precipitation from NOAA’s grid at Islandia’s center; snow, wet days and snow on the ground from Islip Li Macarthur Airport. 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January40°23°3.5"10.3"11724° – 38°
February42°24°3.1"9.4"10921° – 39°
March49°31°4.4"6.5"11435° – 48°
April60°40°4.0"0.6"11046° – 54°
May69°49°3.5"0.0"12055° – 63°
June79°59°4.0"0.0"10066° – 72°
July84°65°3.4"0.0"9070° – 78°
August82°64°3.8"0.0"9069° – 77°
September75°57°3.9"0.0"9064° – 70°
October65°46°4.2"0.0"9051° – 62°
November54°36°3.5"0.5"10040° – 50°
December45°29°4.5"4.5"12330° – 48°
Year62°44°45.6"31.8"12223
Year to year

How much a month can swing

A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 30° to 48°. June is the most reliable, staying within 7°.

Coldest to warmest month in 30 yearsNormal
Sources

Where Islandia’s numbers come from

Normals are 30-year averages, not a forecast. How TownRatings reads climate data →

  • Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Islandia’s center.
  • Snow: Islip Li Macarthur Airport.
  • Frost, freezing nights, 90° and 100° days, heating and cooling: Islip Li Macarthur Airport, 4 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
  • Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
  • Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
  • Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).

Common questions about Islandia’s climate

What is the weather like in Islandia?

A typical July afternoon reaches 84°, a January night drops to 23°, and about 32 inches of snow falls in a normal winter. Milder January nights than 58% of U.S. towns; cooler July afternoons than 62% of U.S. towns.

How cold does it get in Islandia in winter?

January nights average 23°. About 98 nights a year reach 32° or below. In the coldest January of the last 30 years the month averaged 24°.

How much snow does Islandia get?

About 32 inches in a normal winter at Islip Li Macarthur Airport, heaviest from January through February, about 10 inches a month, with snow on the ground about 23 days a year.

How hot does it get in Islandia?

July, with a typical high of 84° and a low of 65°. About 8 days a year reach 90° (Islip Li Macarthur Airport).

When is the first and last frost in Islandia?

In half of years the last spring frost (32°) comes by April 10 and the first fall frost by November 2, about 207 frost-free days, at Islip Li Macarthur Airport.

What growing zone is Islandia in?

Zone 7b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 6°.

What is the best time of year to visit Islandia?

By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.

Is Islandia getting warmer?

Yes: 1991–2020 averaged 2.3° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 98% of U.S. towns.

Neighbors talk weather

Gardens, snow, and the best days of the year in Islandia.

Town Square →
Ask your neighbors

Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.