Islip LI Macarthur, NY Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from Islip LI Macarthur's primary NOAA station, ISLIP LI MACARTHUR AP.
The climate verdict for Islip LI Macarthur
Water is the standout signal in Islip LI Macarthur, New York: 46.0 inches of precipitation in a normal year. Against that wet profile, NOAA records an annual average of 53°F. Its climate comfort score of 63/100 (good) lands mid-pack nationally, exceeding 46% of station-mapped location scores.
- 53°F
- yearly average temperature, NOAA normal
- 63/100
- comfort score, above 46% of station-mapped location scores
- 46.0"
- annual precipitation · 32" snow
- 206 days
- growing season, frost-free days
Islip LI Macarthur: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00004781 · Islip LI Macarthur, NY 53°F mean · 46.0" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-MID · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 53°F
- RANK-MID #3,705
- PHOTO-FINISH ≈ Stonewall Jacks…
- PRCP-MID 46.0"
- SWING-MID 43°F
- COMF-MID 63/100
- LOAD-HEAT 5,183 HDD
- STN-1 USW00004781
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Stonewall Jackson Dam, WV (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every NY station list.
- Islip LI Macart… (this station) 53°F
- Cold Moorefield, WV 53°F
- Hot Aztec Ruins Nat…, NM 53°F
- Near Stonewall Jacks…, WV 53°F
- Near Woodstock, VA 53°F
Climate Living Index · Islip LI Macarthur
Islip LI Macarthur: 61/100 · grade C
Islip LI Macarthur publishes 5 of 6 Living Index dimensions (NOAA annual/seasonal normals · NOAA daily multivariate normals); 1 missing weight rescale to 100.
PlainClimate-derived for Islip LI Macarthur, not an official NOAA rating. Rankings still use Comfort Score 63/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Normal heat + freeze calendar | 101 calendar days | 75/100 · B |
| Frost-free season | 206 days/year | 69/100 · C |
| Precipitation balance | 46.0 in · 11.0 from 35 in | 61/100 · C |
| Annual temperature balance | 53.1°F · 14.4° from 67.5°F | 53/100 · D |
| Snowfall burden | 31.8 inches/year | 36/100 · F |
Islip LI Macarthur · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Islip LI Macarthur is a continental Köppen climate: Dfa
Coldest-month mean 31.9°F and warmest-month mean 75.0°F place this station in continental, no dry season, hot summer climates (Dfa). Class Dfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, hot summer.
- Köppen code
- Dfa
- Group
- Continental
- Warmest month
- 75.0°F
- Coldest month
- 31.9°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Islip LI Macarthur sits across the climate record
Three NOAA fields for Islip LI Macarthur's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 54th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- Top 29% wettest
- Islip LI Macarthur's annual total ranks in the wetter third of 6,352 measured normals.
- Seasonal temperature swing
- 49th percentile swing
- Typical seasonal amplitude versus 6,861 complete station-years.
How Islip LI Macarthur compares across U.S. station-mapped locations
Islip LI Macarthur's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
63 46th percentile score exceeds 46% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). This entry sits in this band.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Islip LI Macarthur's measured station temperature trend
MethodologyAcross 58 complete annual observations from 1964 to 2024, ISLIP LI MACARTHUR AP warmed at a fitted rate of 0.31°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Islip LI Macarthur primary station fitted change +0.31 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 39°F (4°C) | 25°F (-4°C) | 32°F (0°C) | 3.7" | 10.3" | 24.8 | 0.0 |
| February | 41°F (5°C) | 26°F (-4°C) | 33°F (1°C) | 3.3" | 9.4" | 22.3 | 0.0 |
| March | 48°F (9°C) | 32°F (0°C) | 40°F (4°C) | 4.5" | 6.5" | 16.9 | 0.0 |
| April | 58°F (15°C) | 41°F (5°C) | 50°F (10°C) | 4.1" | 0.6" | 3.3 | 0.0 |
| May | 68°F (20°C) | 51°F (10°C) | 60°F (15°C) | 3.3" | 0.0" | 0.0 | 0.3 |
| June | 77°F (25°C) | 61°F (16°C) | 69°F (21°C) | 4.0" | 0.0" | 0.0 | 1.5 |
| July | 83°F (28°C) | 67°F (20°C) | 75°F (24°C) | 3.3" | 0.0" | 0.0 | 4.1 |
| August | 81°F (27°C) | 66°F (19°C) | 74°F (23°C) | 4.2" | 0.0" | 0.0 | 2.2 |
| September | 75°F (24°C) | 59°F (15°C) | 67°F (19°C) | 3.6" | 0.0" | 0.0 | 0.2 |
| October | 64°F (18°C) | 47°F (8°C) | 56°F (13°C) | 4.0" | 0.0" | 0.8 | 0.0 |
| November | 54°F (12°C) | 38°F (3°C) | 46°F (8°C) | 3.4" | 0.5" | 9.3 | 0.0 |
| December | 44°F (7°C) | 30°F (-1°C) | 37°F (3°C) | 4.7" | 4.5" | 20.9 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 83°F around July 16, short of 90°F on every date, while 101 dates carry a normal low at or below freezing, the coldest 24°F near January 26.
The freezing stretch
The normal low stays at or below 32°F into March 16, then returns to freezing around December 7, covering 101 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is April 14, when 38% of years recorded at least a hundredth of an inch. The driest is September 4 at 27%. Summed across the calendar, that is about 122 wet dates a year.
The widest day
April 30 carries the biggest normal gap between afternoon and dawn, 18°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Islip LI Macarthur.
Where Islip LI Macarthur Stands Nationally
Among the steadiest day-night climates ranked: even the widest normal daily swing holds to roughly 18°F.
Islip LI Macarthur earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 10.3"
11.1 days with precipitation
Snow: 9.4"
9.9 days with precipitation
Snow: 6.5"
10.8 days with precipitation
Snow: 0.6"
11.3 days with precipitation
11.6 days with precipitation
10.1 days with precipitation
9.1 days with precipitation
8.9 days with precipitation
8.6 days with precipitation
9.2 days with precipitation
Snow: 0.5"
9.6 days with precipitation
Snow: 4.5"
11.8 days with precipitation
Islip LI Macarthur spreads its precipitation across the year
Neither half of the year dominates here: June through August take 25% of the annual total and December through February 25%, with neither reaching the 35% that would mark a distinct wet season. Islip LI Macarthur has no dry season to plan around, though it does carry a 43.1°F seasonal spread.
The gap between the wettest and driest month still matters: December averages 4.7" and July 3.3". The three wettest months together take 29% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
When it rains in Islip LI Macarthur, it arrives in quantity
46.0" of precipitation falls across only about 122 wet days here, averaging 0.38 inches each. Fewer days carry more water: the year's total is delivered in comparatively heavy events rather than persistent damp.
- Days with measurable precipitation
- about 122 a year, 33% of all days
- Average depth per wet day
- 0.38 inches
- Most wet days
- December, about 12
- Fewest wet days
- September, about 9
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year, and a per-day average is not a forecast of any individual storm.
Winter brings real snow to Islip LI Macarthur
Islip LI Macarthur averages 31.8 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 13 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 31.8 inches of depth.
- Days recording measurable snow: about 13 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 7% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
November 2
50% probability date
Last Spring Freeze
April 10
50% probability date
Growing Season
206 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,183
Higher = more heating needed
Cooling Degree Days
885
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Nationwide similar cities
Other rankable U.S. places outside NY closest to Islip LI Macarthur on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (53°F here).
- Allentown, PA 53°F · 0.0°F off
- Dallas, OR 53°F · 0.0°F off
- Danville, IL 53°F · 0.0°F off
- Decatur, IL 53°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (46.0" here), excluding temperature-peer places.
- Brookneal, VA 46.0" · 0.0" off
- Columbus, KS 46.0" · 0.0" off
- Lane, OK 46.0" · 0.0" off
- Atlantic City, NJ 46.0" · 0.0" off
Snow and freeze rhythm
When cold and snow define Islip LI Macarthur
heating led · wet · mid swing
Islip LI Macarthur's energy balance leans toward cold weather: 5,183 annual heating degree days against 885 for cooling. Its 43.1°F seasonal range still makes the monthly rows more useful than the annual average alone.
Islip LI Macarthur's frost-free season lasts about 206 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Islip LI Macarthur coldest normal
January
The monthly mean of 32°F (0°C) sits near freezing, so cold nights and above-freezing afternoons share the same month.
-
2. Islip LI Macarthur typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Islip LI Macarthur snow peak
January
Islip LI Macarthur averages 31.8 inches of snow a year, with January the snowiest month on the normals.
Questions about Islip LI Macarthur's climate
How much snow does Islip LI Macarthur get? ▼
How cold does Islip LI Macarthur get in winter? ▼
How much energy does heating and cooling require in Islip LI Macarthur? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Islip LI Macarthur's primary station: ISLIP LI MACARTHUR AP (USW00004781). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The conservative exact name-and-state crosswalk finds no Census place match, so PlainClimate treats this as a station-mapped location and does not claim it is a municipality. No exact Gazetteer row for Islip LI Macarthur; facility counts that depend on place identity are therefore an upper bound, not a municipal census.
On this page every temperature, precipitation, and derived score for Islip LI Macarthur comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.