High Surf Advisory — Southern Bristol, MA, Southern Plymouth, MA, Barnstable, MA, Dukes, MA, Nantucket, MA, Washington, RI, Newport, RI, Block Island, RI 7:00 PM

Nantucket, Massachusetts

Last updated: 2:18 PM CDT  ·  Refresh
23°C
Feels like 21°
Overcast
▲ 23°  /  ▼ 21°
Wind
18 mph SE
Humidity
82%
Dew Point
19°
Pressure
29.92 inHg
Visibility
10 mi
UV Index
2.8
Cloud Cover
96%
Sunrise
5:25 AM
Sunset
8:07 PM
Drag to pan · double-click to forecast a point
WeatherAI™ Analysis

WeatherAI Analysis: Nantucket is currently overcast at 23°C. Precipitation is likely — peak probability 90% around 6 PM. Atmospheric instability is elevated (CAPE up to 523 J/kg) — isolated convective development possible. Sunrise: 5:25AM · Sunset: 8:07PM.

Alerts

High Surf Advisory
Southern Bristol, MA, Southern Plymouth, MA, Barnstable, MA, Dukes, MA, Nantucket, MA, Washington, RI, Newport, RI, Block Island, RI
Expires 7:00 PM
61 AQI · Moderate Dominant: PM2.5 Air Quality
Hourly Forecast · Next 24 Hours
Now
23°
36%
4 PM
23°
60%
5 PM
22°
88%
6 PM
22°
90%
7 PM
22°
90%
8 PM
22°
90%
9 PM
22°
90%
10 PM
22°
90%
11 PM
22°
90%
12 AM
22°
90%
1 AM
22°
90%
2 AM
22°
85%
3 AM
22°
79%
4 AM
21°
90%
5 AM
22°
90%
6 AM
22°
90%
7 AM
22°
81%
8 AM
22°
85%
9 AM
22°
82%
10 AM
23°
82%
11 AM
23°
77%
12 PM
23°
77%
1 PM
22°
64%
2 PM
22°
64%
7-Day Forecast
Today
23° 21°
Heavy Rain, 90% chance.
Wed
23° 21°
Rain, 90% chance.
Thu
23° 17°
Overcast with a 74% chance of rain.
Fri
22° 17°
Overcast with a 42% chance of rain.
Sat
21° 18°
Clear with a 25% chance of rain.
Sun
22° 19°
Drizzle, 81% chance.
Mon
23° 19°
Drizzle, 60% chance.
TimeTempConditionsPrecipWindHumidity
Now 23° Overcast 36% 18 mph SE 82%
4 PM 23° Overcast 60% 21 mph SSE 85%
5 PM 22° Heavy Rain 88% 23 mph SSE 90%
6 PM 22° Heavy Rain 90% 22 mph SSE 95%
7 PM 22° Overcast 90% 21 mph S 96%
8 PM 22° Heavy Rain 90% 22 mph S 96%
9 PM 22° Thunderstorm 90% 24 mph S 96%
10 PM 22° Heavy Rain 90% 27 mph S 96%
11 PM 22° Overcast 90% 28 mph S 96%
12 AM 22° Overcast 90% 27 mph SSW 96%
1 AM 22° Overcast 90% 26 mph SSW 96%
2 AM 22° Heavy Rain 85% 25 mph SSW 95%
3 AM 22° Heavy Rain 79% 25 mph SSW 95%
4 AM 21° Heavy Rain 90% 26 mph SSW 95%
5 AM 22° Heavy Rain 90% 25 mph SSW 94%
6 AM 22° Rain 90% 23 mph SSW 95%
7 AM 22° Rain 81% 22 mph SSW 95%
8 AM 22° Rain 85% 22 mph SSW 96%
9 AM 22° Rain 82% 23 mph SSW 96%
10 AM 23° Rain 82% 23 mph SSW 95%
11 AM 23° Rain 77% 23 mph SSW 95%
12 PM 23° Rain 77% 22 mph SSW 95%
1 PM 22° Rain 64% 22 mph SSW 94%
2 PM 22° Rain 64% 22 mph SSW 94%
15-Day Forecast
Today
7/21
Heavy Rain
90%
21°
23°
Wed
7/22
Rain
90%
21°
23°
Thu
7/23
Overcast
74%
17°
23°
Fri
7/24
Overcast
42%
17°
22°
Sat
7/25
Clear
25%
18°
21°
Sun
7/26
Drizzle
81%
19°
22°
Mon
7/27
Drizzle
60%
19°
23°
Tue
7/28
Drizzle
60%
21°
23°
Wed
7/29
Drizzle
60%
20°
22°
Thu
7/30
Drizzle
60%
21°
22°
Fri
7/31
Drizzle
60%
21°
22°
Sat
8/1
Rain
90%
21°
22°
Sun
8/2
Drizzle
60%
21°
22°
Mon
8/3
Drizzle
60%
21°
23°
Tue
8/4
Drizzle
60%
21°
23°
61
Moderate
U.S. Air Quality Index · Dominant: PM2.5
50 100 150 200

Air quality is acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.

Pollutant Breakdown · Today
PM2.5
Fine particulate matter
Dominant
61 AQI 14.5 µg/m³
O3
Ground-level ozone
37 AQI 41 ppb
3-Day Outlook
DayAQICategoryO₃PM2.5
Wed 61 Moderate 37 61
Thu 38 Good 38 38
Fri 28 Good 28 28
About the Air Quality Index
0–50 Good
51–100 Moderate
101–150 Unhealthy for Sensitive Groups
151–200 Unhealthy
201–300 Very Unhealthy
301–500 Hazardous

The U.S. AQI runs 0–500. The overall value equals the highest individual pollutant sub-index, and the dominant pollutant is the one driving it. PM2.5 (fine particles) is reported in µg/m³ and ozone (O3) in ppb. Forecast source: NWS NAQFC.

1000850700500400300250200150100 -40-30-20-10010203040 0.41247101624 LCL0°C Temperature (°C) Pressure (hPa)
Temp Dewpoint Parcel (SB) CAPE CIN Dry adiabat Moist adiabat Mixing ratio
RAP
Valid Tue Jul 21, 18:00'Z' · F0 · 130 (13 km CONUS/NA)
Hodograph · kt
10 20 30 40 50 60 SM
0–1 1–3 3–6 6–9 km
Instability
SBCAPE0 J/kg
MLCAPE11 J/kg
MUCAPE0 J/kg
SBCIN-5736 J/kg
MLCIN0 J/kg
Lifted Index1.1
Kinematics
0–6 km Shear36 kt
0–1 km Shear16 kt
Eff. Shear—
0–1 km SRH43
0–3 km SRH-20
Eff. SRH—
Storm Motion189° @ 35 kt
0–1 km EHI0.0
Composite Parameters
Sig. Tornado0.0
STP (eff)—
Supercell—
K-Index28.2
Thermo & Levels
PWAT1.59 in
0–3 km LR5.2 °C/km
700–500 LR5.5 °C/km
Total Totals43.5
LCL951 hPa
LFC—
EL—
Freezing Lvl15,013 ft