WxDecoder

B18 Weather Alton Bay Seaplane Base

Alton Bay, New HampshireElevation 504 ftSeaplane base
OFF-FIELD REFERENCE
Nearest report: KLCI · 10 NM NW · 51 min old
No ceiling, visibility 10 SM.
No on-field report, so no field flight category. Conditions at the field may differ.
OFF-FIELD REFERENCE · KLCI
WIND
Calm
no steady wind
VISIBILITY
10 SM
16.1 km
CEILING
None
no BKN/OVC layer
FORECAST & PILOT NOTES · SUPPLEMENTAL

Extended forecast and pilot notes

No aviation METAR is published for this airport. The nearest National Weather Service station reports wind calm, visibility 10 SM, temperature 4C. Treat this as supplemental, not an aviation observation. Forecast suggests tonight mostly clear, low near 37F, 0% chance of precipitation. Key risks: no significant hazards are highlighted right now, but always confirm against an official briefing.

DayConditionsTemp FWindGustsPrecipPilot note
Tonight Mostly Clear 37 SW 4 kt – 0%
Monday Sunny 65/35 W 9 kt – 6%
Tuesday Sunny 51/29 NW 4 kt – 0%
Wednesday Sunny 54/37 W 4 kt – 0%
Thursday Sunny 65/47 SW 9 kt – 6%
Friday Mostly Sunny 66/41 W 9 kt – 5%
Saturday Mostly Sunny 62/44 W 4 kt – 7%
Sunday Partly Sunny then Slight Chance Rain Showers 63 SW 4 kt – 17%

Source: National Weather Service (office GYX). Forecast issued 2345Z.

Radar

Radar data: NOAA/NWS MRMS composite reflectivity. For situational awareness only, not a substitute for an official weather briefing.

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RUNWAYS & WIND
Crosswind calculator
No runway layout is available for B18. Enter a runway number or heading to estimate wind components.
RUNWAYS

Runway detail & declared distances

1 runway · longest 2,600 ft

01W/19W
Dimensions
2,600 x 100 ft
Surface
Water (excellent)
RWY 01W
RWY 19W

Runway data from the FAA NASR dataset (effective 2026-06-11). Verify with the current Chart Supplement and NOTAMs.

FIELD CONDITIONS

Field elevation

Field elevation
504 ft MSL

Density and pressure altitude need a current temperature and altimeter from the METAR.

DAYLIGHT & NIGHT

Sun & logging windows

Sunset
2146Z 5:46 PM
Sunrise
1112Z 7:12 AM
Loggable night
2215Z (6:15 PM local) → 1043Z (6:43 AM local)
end of evening to start of morning civil twilight
Position lights required
2146Z (5:46 PM local) → 1112Z (7:12 AM local)
sunset to sunrise (91.209)
Night passenger currency
2246Z (6:46 PM local) → 1012Z (6:12 AM local)
1 hr after sunset to 1 hr before sunrise (61.57(b))

FAA definitions, shown in Zulu with airport-local time. Verify for your operation.

AIRPORT INFORMATION

Facility & services

Alton Bay Seaplane Base is in Alton Bay, New Hampshire. Field elevation 504 ft MSL. Airport facts are drawn from OurAirports and the FAA NASR dataset.

OPERATIONS & CONTACT
OwnershipPublicly owned
UseOpen to the public
TypeSeaplane base
ManagerJASON LEAVITT
Manager phone603-545-2315
AttendedUNATNDD
CHARTS & AIRSPACE
ICAO / IATAB18
SectionalNEW YORK
Center (ARTCC)BOSTON
Flight service (AFSS)BANGOR
RegionNew Hampshire
CountryUnited States
Coordinates43.4776, -71.2370
Distance from city2 NM N
SERVICES & LIGHTING
Control towerNon-towered
CTAF122.800
UNICOM122.800
FREQUENCIES

Communications

122.800
CTAF
CTAF
122.800
UNICOM
UNICOM

Not all tower/ground/approach frequencies are in our datasets. Verify with the FAA Chart Supplement.

AIRCRAFT ACTIVITY

B18 traffic patterns

2026-09-25 to 2026-10-15, 4 days observed · data 2026-10-23

Low confidence
TRAFFIC VOLUME (30-DAY)
AVG LANDINGS/DAY
1.3
AVG OPS/DAY
2.3
Activity trend over 4 days: falling, from 4 to 1 operations per dayOperations trend (4 days)

Busiest day: Fri · Busiest month: Sep

FLEET MIX
Piston single 60%Unknown 40%

Mostly small piston aircraft.

TOP AIRCRAFT TYPES
›PETR (Unknown) · ~2 landings/mo
›C175 (Piston single) · ~1 landings/mo
›SREY (Piston single) · ~1 landings/mo
›T206 (Piston single) · ~1 landings/mo
LIKELY BASED AIRCRAFT
Low-confidence estimate

Aircraft likely based near this airport (estimate), mostly aircraft of unknown type.

›PETR (Unknown)

This is an estimate based on repeated flight patterns, not registration data. Do not rely on it to identify specific aircraft or owners.

Data limitations (4)
›ADS-B coverage is incomplete; counts are an observed lower bound, not official totals.
›Some aircraft do not transmit usable ADS-B and are not counted.
›Aircraft types and based estimates are inferred and may be wrong.
›This is not official ATC, FAA, or airport data.
NEARBY AIRPORTS

Weather reference stations

B18 has no on-field report. Nearest reporting station: KLCI (10 NM NW, VFR).

KLCI Laconia Municipal Airport
10 NM NW
VFR
KCON Concord Municipal Airport
20 NM SW
VFR
KSFM Sanford Seacoast Regional Airport
24 NM E
VFR
KPSM Portsmouth International Airport at Pease
30 NM SE
VFR
KIZG Eastern Slopes Regional Airport
33 NM N
VFR
KMHT Manchester-Boston Regional Airport
34 NM S
VFR
AIRPORT REMARKS

Operational remarks

›FOR CD CTC BOSTON APCH 603-594-5552.
›ALL SEAPLANE TKOFS & LDGS MUST BE N OF THE BANDSTAND. ALL TVL S OF THE BANDSTAND MUST NOT EXCEED HEADWAY SPD.
›PUBLIC WATERS OF THE STATE OF NH.
›TKOF & LDG USING RWY 19W PROHIBITED JAN - MAR.
›RWY 01W THLD APRXLY 100 FT NE OF FLOATING BANDSTAND.
›FOR SEAPLANE PRKG & ICE RWY CONDS CALL 603-271-7398.
›RWY 01W/19W HAS ICE IN WINTER PLOWED TO APRXLY 2600 FT. CK NOTAMS FOR ICE RWY CONDS.
›VFR USE ONLY.
›RWY 01W/19W PWRLINE MKD WITH ORANGE BALLS 1000 FT S OF THR AT S END; LESS THAN 30 FT HGT ALG ROADWAY.
OFFICIAL LINKS & SOURCES
↗Search NOTAMs (official FAA NOTAM Search)
↗Wikipedia
↗B18 on OurAirports
FREQUENTLY ASKED
Does B18 have a METAR?
No on-field METAR is issued for B18. This page uses the nearest reporting station as a reference.
Does B18 have a TAF?
No TAF is issued directly for B18. Use the nearest TAF-issuing field as a planning reference.
What is the field elevation at B18?
B18 sits at 504 ft MSL, which factors into the density-altitude estimate on this page.
Is this an official preflight weather briefing for B18?
No. wxdecoder.com is for education and situational awareness only. It is not an official weather briefing or a substitute for official sources, NOTAM review, and pilot judgment.
This app is for aviation weather education, training, and situational awareness only. It is not a substitute for an official weather briefing, approved flight-planning software, flight service, dispatch procedures, current FAA regulations, or pilot judgment. Always verify weather with official sources before flight.