WxDecoder

81LL Weather Otterbach Farm Airport

Mendota, IllinoisElevation 840 ftSmall airport
OFF-FIELD REFERENCE
Nearest report: KVYS · 13 NM S · More than 1 hour old
No ceiling, visibility 10 SM.
No on-field report, so no field flight category. Conditions at the field may differ.
OFF-FIELD REFERENCE · KVYS
WIND
170@4
steady
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 visibility 10 SM. This observation is older than usual, so treat it with extra caution. Treat this as supplemental, not an aviation observation. Forecast suggests tonight partly cloudy, low near 51F, 1% chance of precipitation. Key risks: thunderstorms in the forecast.

PILOT WEATHER NOTES
Thunderstorms in the forecastWeather.gov
Thursday: Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms. Watch for developing convection and plan alternates.
DayConditionsTemp FWindGustsPrecipPilot note
Tonight Partly Cloudy 51 0 kt – 1%
Monday Mostly Cloudy 68/48 NE 9 kt – 3%
Tuesday Partly Sunny 72/54 SE 9 kt – 3%
Wednesday Mostly Sunny 74/57 S 9 kt – 15%
Thursday Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms 76/56 SW 9 kt – 35% Thunderstorms in the forecast
Friday Chance Showers And Thunderstorms 75/57 SSE 4 kt – 35%
Saturday Chance Rain Showers 71/56 S 4 kt – 55%
Sunday Chance Rain Showers 70 SW 4 kt – 33%

Source: National Weather Service (office DVN). Forecast issued 0248Z.

Radar

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

OUR HEADSET PICK · NOT SPONSORED

DC

David Clark DC ONE-X

Not sponsored, just the headset we'd buy ourselves: the DC ONE-X, with hybrid noise canceling, Bluetooth, and 30+ hour battery. And David Clark's A+ customer service is the real reason we recommend them.

Visit David Clark
RUNWAYS & WIND
Crosswind calculator
No runway layout is available for 81LL. Enter a runway number or heading to estimate wind components.
RUNWAYS

Runway detail & declared distances

1 runway · longest 1,600 ft

NW/SE
Dimensions
1,600 x 70 ft
Surface
Turf
RWY NW
RWY SE

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
840 ft MSL

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

DAYLIGHT & NIGHT

Sun & logging windows

Sunset
2300Z 6:00 PM
Sunrise
1221Z 7:21 AM
Loggable night
2329Z (6:29 PM local) → 1152Z (6:52 AM local)
end of evening to start of morning civil twilight
Position lights required
2300Z (6:00 PM local) → 1221Z (7:21 AM local)
sunset to sunrise (91.209)
Night passenger currency
0000Z (7:00 PM local) → 1121Z (6:21 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

Otterbach Farm Airport is in Mendota, Illinois. Field elevation 840 ft MSL. Airport facts are drawn from OurAirports and the FAA NASR dataset.

OPERATIONS & CONTACT
OwnershipPrivately owned
UsePrivate use
TypeSmall airport
ManagerDEAN L. OTTERBACH
Manager phone773-538-7102
AttendedUNATNDD
CHARTS & AIRSPACE
ICAO / IATA81LL
SectionalCHICAGO
Center (ARTCC)CHICAGO
Flight service (AFSS)KANKAKEE
RegionIllinois
CountryUnited States
Coordinates41.5723, -89.1714
Distance from city2 NM NW
SERVICES & LIGHTING
Control towerNon-towered
AIRCRAFT ACTIVITY

Traffic patterns

Aircraft activity data is not available for this airport yet.

NEARBY AIRPORTS

Weather reference stations

81LL has no on-field report. Nearest reporting station: KVYS (13 NM S, VFR).

KVYS Illinois Valley Regional Airport Walter A Duncan Field
13 NM S
VFR
KSQI Whiteside County Airport - Joseph H Bittorf Field
25 NM NW
VFR
KARR Aurora Municipal Airport
33 NM E
VFR
KRFD Chicago Rockford International Airport
38 NM N
VFR
KFEP Albertus Airport
44 NM NW
VFR
KJOT Joliet Regional Airport
45 NM E
VFR
AIRPORT REMARKS

Operational remarks

›OWNER DESIRES ARPT NOT BE CHARTED.
›E111:PROVIDED ALL TRAFFIC PATTERN OPERATIONS ARE CONDUCTED NORTH OF THE RWY.
›KEN OTTERBACK 35461 N 2900TH RD MENDOTA, IL 61342 (815) 538-7102
›FOR CD CTC CHICAGO ARTCC AT 630-906-8921.
OFFICIAL LINKS & SOURCES
↗Search NOTAMs (official FAA NOTAM Search)
↗81LL on OurAirports
FREQUENTLY ASKED
Does 81LL have a METAR?
No on-field METAR is issued for 81LL. This page uses the nearest reporting station as a reference.
Does 81LL have a TAF?
No TAF is issued directly for 81LL. Use the nearest TAF-issuing field as a planning reference.
What is the field elevation at 81LL?
81LL sits at 840 ft MSL, which factors into the density-altitude estimate on this page.
Is this an official preflight weather briefing for 81LL?
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.