Are NOTAMs in local or Zulu time?

Quick answer: pilots should read aviation time windows on one UTC/Zulu clock unless a particular source clearly labels a local-time display. That includes checking the date, not just the hour. A runway closure that starts at 0200Z may be the prior evening in local time.

The FAA says pilots must become familiar with all available information concerning the flight, including runway lengths, takeoff and landing distance data, weather reports and forecasts, fuel requirements, and alternatives when a flight cannot be completed as planned under 14 CFR § 91.103. NOTAM timing is part of that preflight picture.

Why this matters

NOTAMs are often operationally simple but time-sensitive: runway closed, taxiway closed, lighting out of service, approach unavailable, temporary tower hours, obstacle light unserviceable, or airspace active. If you read the time window on the wrong clock, you can decide that a restriction is inactive when it is active, or active when it is no longer relevant.

A safe way to read NOTAM time windows

1. Keep the original UTC/Zulu time intact. Write down the day and time before converting anything.
2. Convert both start and end times. Do not convert only the beginning of the window.
3. Check the local date. Evening local time can be the next Zulu day; early Zulu time can be the prior local evening.
4. Compare against ETA, not departure time only. A NOTAM at the destination or alternate matters when you get there.
5. Use an official briefing source. Flight Service and FAA-approved briefing channels are the right place to confirm NOTAM status before flight.

Example: 0200Z is not always "tomorrow" locally

Suppose a NOTAM is effective from 0200Z to 0500Z on the 27th. In Eastern Daylight Time, that is 10:00 PM to 1:00 AM local, beginning on the evening of the 26th. If you only read the Zulu date, you may think the closure starts tomorrow when it actually starts tonight.

METARs, TAFs, and NOTAMs belong on the same clock

Aviation weather products also use Zulu/UTC timing. Aviation Weather Center publishes METAR and TAF data at aviationweather.gov, and those reports are designed to be compared on a shared UTC clock. Put your TAF validity window, NOTAM window, ETA, and fuel stop timing on the same clock before making the go/no-go decision.

Use a converter, but understand the check

A converter is faster than doing date math in your head, especially when a route crosses time zones. The Aero Companion pilot UTC / Zulu time converter keeps origin, destination, UTC, and return-at-origin times visible together. The mental check is still useful: add the local offset to local time, then adjust the date if the result passes midnight.

For the full conversion method, see How to calculate Zulu time. For route-level planning, pair NOTAM timing with the VFR flight plan guide.