METAR & TAF REPORTS

> Part 2 of 6

Course Dashboard

Report Issue Times
& Valid Periods

Is This Weather Data Still Valid?

MISSION: Pawnee Grassland Summer Documentation

Field Notes: Checking Data Freshness

T-minus 24 hours | Is this forecast fresh?

It’s Tuesday evening, 6:00 PM. You’re at home reviewing the TAF report for tomorrow’s potential flight to Pawnee. in the previous lesson you said you were looking at Thursday and Friday, not Wednesday

You find the TAF for KFNL (Fort Collins-Loveland Airport, the closest reporting station to Pawnee). The forecast looks promising at first glance—but then you pause.

Wait. When was this even issued?

You notice all the timestamps end with a “Z.” You remember from your training that aviation weather uses ZULU time (also called UTC) instead of local time. This means you’ll need to convert between your local time and ZULU time to figure out when reports were issued and what periods they cover. Good thing you’re learning that skill in this lesson.

You’ve heard stories of pilots checking weather reports without realizing they were looking at old data. A TAF issued 18 hours ago might not reflect current atmospheric changes. A METAR from this morning doesn’t tell you what’s happening right now.

Before you can trust any weather data, you need to answer two critical questions based on the information on the TAF report:

  • Question 1: When was this forecast issued?
  • Question 2: What time window does it actually cover?

To answer question one, you scan the TAF and spot the issue time at the beginning of the report. It was published just three hours ago, meaning it’s still relevant. Perfect. You’re a go.

To answer question two, you find the forecast valid period. It shows the report’s forecast period ranges from this evening through tomorrow night. You do a quick mental check: your planned golden hour window tomorrow between 5:30pm and 8:30pm. It’s covered. You’re a go.

You also make a mental note that when you arrive at the flight site tomorrow you’ll also check the most recent METAR report to get real-time weather.

Here’s what you just learned: Before diving into reading weather on these reports, you need to know if the report is even relevant to your mission.

Always check when the report was issued and what time period it covers.

In This Lesson You’ll Learn:

  • How to read the timestamp and forecast periods for both METAR and TAF reports
  • What Zulu Time is and why the FAA’s radio-comms protocols use it.

What is Zulu Time?

Zulu is the aviation name for UTC: Coordinated Universal Time.

It is a standardized 24-hour format used around the world in aviation.

Zulu Time is used because having a universal standard for time avoids confusion between different time zones around the world.

With Zulu Time pilots and air traffic controllers can rely on a consistent, globally-recognized time reference when interpreting weather reports, regardless of their location.

METAR & TAF

Report Issue Date and Time

On both TAF and METAR Reports you’ll see the issue time structured the same way.

Let’s look at the following example of a METAR report issued at: “121200 Zulu Time”.

  • The first 2 digits indicate the day of the month. (12th day of the month)
  • That is followed by the Zulu time in a four-digit format. (12:00 Zulu time)

Therefore we know that, “121200 Zulu Time” means the METAR report was issued on 12th day of the month at 12:00 Zulu.

Here’s another example:

  • 101000Z is the reported issue time, meaning the report was issued on the 10th day of the month at 10:00 Zulu time (UTC).

Additional “Issue Date & Time” Examples:

TAF ONLY

Forecast Period

TAF Reports will display additional lines showing the forecast period and other time stamps indicating weather shifts during the window.

Here’s what you can expect to see:

  • You’ll see the forecast period displayed as follows 1218/1318. The numbers before and after the slash indicate the day of the month followed by the hour when the forecast starts and ends. Specifically what the forest period of 1218/1318 is telling letting you know the valid window begins on the 12th day of the month at 18:00 Zulu (i.e. 1218) and ends the following day on the 13th day of the month at 18:00 Zulu (i.e. 1318).

Flash Cards

Practice Reading Zulu Time

Hover your cursor over flashcards to view answer.

Issue Time (METAR & TAF)

110200Z

02:00 UTC on the 11th day of the month

151830Z

18:30 UTC on the 15th day of the month

040745Z

07:45 UTC on the 4th day of the month

Forecast Period (TAF ONLY)

1218/1324Z

Forecast Period:

1800Z on the 12th day to 2400Z on the 13th day.

0915/1003Z

Forecast period from 15:00 UTC on the 9th to 03:00 UTC on the 10th

2812/0112Z

Forecast period from 12:00 UTC on the 28th to 12:00 UTC on the 1st

FM2200

From 2200 Zulu time...

Practice Quiz

METAR vs. TAF Reports (Reading Time)

1 / 8

Why do METAR and TAF reports use Zulu Time (UTC) to display issue times and forecast periods?

2 / 8

A METAR report lists the issue time as “231745Z.” What does this indicate?

3 / 8

A METAR report for KBOI lists the issue time as 121854Z. When was this METAR report issued?

4 / 8

A TAF report shows an issue time of “050630Z.” How should this time be interpreted?

5 / 8

A TAF report for KMEM lists the issue time as 121720Z. When was this TAF report issued?

6 / 8

A TAF report for KOKC lists the issue time as 051130Z. When was this TAF report issued?

7 / 8

In the TAF report for KMEN, a highlighted forecast time range reads 1218/1324. What forecast period does this represent?

8 / 8

In the TAF report for KMEN, a highlighted group reads FM0200. What does this indicate?

Your score is

The average score is 88%

0%

You’re forecasted to Ace this exam!

What’s Next?

In the following lessons, you’ll learn to interpret wind codes, visibility notation, weather phenomena abbreviations, and cloud coverage—step by step, on both METAR and TAF Reports.

By the end of this module, you’ll be able to look at any METAR or TAF report and know exactly what conditions to expect.