Brentwood weather in January

In January, Brentwood sees average daytime highs of 39°F and overnight lows near 30°F, with 3.8 in of precipitation across 9.9 wet days and about 9.4 hours of daylight. It is the 12th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 41°F in the first days to 38°F by the end. The sky is clear or mostly clear about 33% of the time in January, and the air most often feels dry.

Daylight stretches from about 9 h 06 min at the start of January to 9 h 48 min by month's end. Set against the rest of the year, January is Brentwood's 7th-clearest and 1st-windiest month. For the whole year in context, see Brentwood's year-round climate.

Daytime high
39°
12th warmest
Overnight low
30°
2nd coldest
Precipitation
3.8 in
9.9 wet days
Daylight
9 h 24 min
7:21 AM – 4:44 PM
Cloud cover
59%
7th clearest
Wind
13 mph
1st windiest
Solar energy
2.11 kWh/m²
Travel score
0.0
out of 10

Brentwood is census-designated place in Suffolk County, New York, United States.

Density
2,136/km²
people per km²

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in January

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 41°F in the first days to 38°F by the end.

A typical January day in Brentwood reaches about 39°F in the afternoon and slips back to 30°F overnight — a 9°F spread between the day's warmth and the night's chill. On most days the high lands between 28°F and 49°F. Set against its neighbours, January runs about 5°F cooler than December and on par with February.

20°30°40°50°60°151015202531
Avg high (°F)Avg low (°F)
14133
24133
34132
44132
54132
64032
74031
84031
94031
104031
114031
123930
133930
143930
153930
163929
173829
183829
193829
203829
213829
223829
233829
243829
253829
263829
273829
283829
293829
303829
313829

How January really feels in Brentwood

Once humidity and wind are folded in, January averages 0 days that feel above 90°F and 31 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
31
wind chill below the day's low

The story in January is cold — wind chill drags the overnight "feels like" below the raw low.

Brentwood weather by month

How January compares with the rest of the year at a glance. January is the 12th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 30°3.89.949.40.0
Feb39° / 30°3.59.33.710.40.0
Mar44° / 35°4.610.62.911.70.8
Apr53° / 44°3.810.90.413.12.8
May61° / 54°3.510.8014.25.0
Jun71° / 64°3.69.9014.96.6
Jul77° / 71°3.39.4014.67.0
Aug77° / 70°3.99.5013.67.1
Sep71° / 64°3.89.1012.36.9
Oct62° / 55°4.49.2010.95.5
Nov53° / 44°3.78.90.39.73.0
Dec44° / 36°4.810.62.39.10.9

Cloud cover in January

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in January.

Beyond those clear spells, partly cloudy skies cover about 15% of January, with mostly cloudy or overcast conditions the remaining 52%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15050
25050
35050
45050
55050
64951
74951
84951
94951
104753
114753
124753
134753
144753
154753
164753
174753
184753
194753
204753
214753
224753
234753
244852
254852
264852
274951
284852
294852
304852
314951

Chance of precipitation in January

Any precipitationSnow

Brentwood gets around 3.8 in of rain and snow over 9.9 wet days in January. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 32% and peaks near 35% on the wettest days, and about 4 days bring snow.

0%10%20%30%40%50%151015202531
Rain chance (%)Snow chance (%)
13310
23311
33311
43411
53412
63412
73412
83512
93513
103513
113513
123513
133513
143413
153413
163413
173313
183313
193213
203213
213113
223013
233013
242913
252913
262913
272913
282913
292913
302913
312913

Humidity in January

DryComfortableHumidMuggyOppressiveMiserable

Most of January feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, January lands in the dry band about 100% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)
1100
2100
3100
4100
5100
6100
7100
8100
9100
10100
11100
12100
13100
14100
15100
16100
17100
18100
19100
20100
21100
22100
23100
24100
25100
26100
27100
28100
29100
30100
31100

Wind in January

Winds average 13 mph in January, the windiest month of the year.

Across January, daily wind ranges from about 12 mph on the calmest days to 13 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
113breezy
213breezy
313breezy
413breezy
513breezy
613breezy
713breezy
813breezy
913breezy
1013breezy
1113breezy
1213breezy
1313breezy
1413breezy
1513breezy
1613breezy
1713breezy
1813breezy
1913breezy
2013breezy
2113breezy
2213breezy
2313breezy
2413breezy
2513breezy
2613breezy
2713breezy
2812breezy
2912breezy
3012light breeze
3112light breeze

Sunrise & sunset in January

DaylightNight

Daylight runs from about 9 h 06 min at the start of January to 9 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 42 minutes over January. Sunrise moves from 7:22 AM to 7:12 AM, and sunset from 4:30 PM to 5:01 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
19.17:224:30
29.17:234:31
39.17:234:31
49.27:234:32
59.27:234:33
69.27:234:34
79.27:234:35
89.27:234:36
99.27:234:37
109.37:224:38
119.37:224:39
129.37:224:40
139.37:224:41
149.37:224:42
159.47:214:43
169.47:214:44
179.47:214:45
189.47:204:46
199.57:204:47
209.57:194:48
219.57:194:49
229.57:184:50
239.67:184:51
249.67:174:53
259.67:164:54
269.77:164:55
279.77:154:56
289.77:144:57
299.77:134:58
309.87:135:00
319.87:125:01

Solar energy in January

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in January, about 2.11 kWh/m².

For context, solar energy here swings from a low near 1.76 kWh/m² to a high of 6.38 kWh/m² in June across the year — January's 2.11 kWh/m² sits near the bottom.

0123151015202531
Solar energy (kWh/m²)Level
11.8Dim
21.8Dim
31.8Dim
41.9Dim
51.9Dim
61.9Dim
71.9Dim
81.9Dim
91.9Dim
101.9Dim
112.0Dim
122.0Dim
132.0Moderate
142.0Moderate
152.1Moderate
162.1Moderate
172.1Moderate
182.1Moderate
192.2Moderate
202.2Moderate
212.2Moderate
222.3Moderate
232.3Moderate
242.3Moderate
252.4Moderate
262.4Moderate
272.4Moderate
282.5Moderate
292.5Moderate
302.5Moderate
312.6Moderate
Planning a trip in January

Hazard calendar for Brentwood

In seasonPeak

None of Brentwood's seasonal hazards are active in January. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Brentwood sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is January a good time to visit Brentwood?

Our two travel scores rate January for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

0.0
Sightseeing
11th-best month of the year
0.0
Beach & pool
9th-best month of the year

January is a weaker month for outdoor sightseeing in Brentwood.

What to pack for Brentwood in January

From January's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In January, Brentwood sees daytime highs around 39°F and nights near 30°F. Pack a warm layer. Worth having: a heavy coat, rain gear and a windbreaker. About 10 days see rain.

a warm layera heavy coatrain geara windbreaker

Sea temperature near Brentwood in January

The nearest coast averages about 43°F in January — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 12 mi away) is warmest in August at about 73°F and coldest in February near 40°F.

It's comfortable for a long swim from Jul 3 to Sep 23 — about 2.7 months when the water holds above 68°F.

40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°F)Comfort
Jan43Bracing
Feb40Bracing
Mar40Bracing
Apr45Bracing
May54Bracing
Jun64Cool
Jul72Refreshing
Aug73Refreshing
Sep70Refreshing
Oct63Cool
Nov55Bracing
Dec49Bracing

UV index in Brentwood in January

LowModerateHighVery highExtreme

Clear-sky midday UV in January peaks around 2. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Brentwood peaks around July 11 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 22 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 11UV 8Dec 22UV 1
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar5Moderate
Apr6High
May7Very high
Jun8Very high
Jul8Very high
Aug6High
Sep6High
Oct3Moderate
Nov2Moderate
Dec1Low

Air quality in Brentwood in January

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where January falls, not just the annual average.

Air quality in Brentwood is worst in July — around 19 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1018 µg/m³Nov 169 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb13Moderate
Mar15Moderate
Apr16Moderate
May18Moderate
Jun18Moderate
Jul19Moderate
Aug16Moderate
Sep13Moderate
Oct10Good
Nov9Good
Dec10Good
Location & terrain

Where is Brentwood?

Brentwood sits at 40.8°N, 73.2°W, 79 ft above sea level, in United States. The nearest listed city is North Bay Shore, 1.9 mi away.

Topography around Brentwood

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Brentwood.

Within 2 miles, the terrain around Brentwood has only modest variations in elevation — a maximum elevation change of 135 ft around an average of 92 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 427 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,207 ft.

The land around Brentwood is covered by trees (46%), artificial surfaces (31%) and grassland (22%) within 2 miles, trees (51%) within 10 miles, and water (52%) and trees (34%) within 50 miles.

2 miles
135 ft
10 miles
427 ft
50 miles
1,207 ft
treesgrasslandartificial surfaceswaterwetland
January weather nearby: North Bay Shore 1.9 mi · Central Islip 2.5 mi · Hauppauge 3.7 mi · Bay Shore 3.7 mi · Islip 3.7 mi · Deer Park 4.3 mi · Commack 5.0 mi · Dix Hills 5.0 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Brentwood (40.7812°, -73.2462°, elevation 79 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).