How to report a 21-knot gust when the 2-minute average wind is 17 knots in LAWRS wind reporting.

Outline

• Opening: Why wind numbers matter in aviation and how gusts fit into the picture

• Scenario spotlight: 2-minute average = 17 knots, gusts up to 21 knots

• The notation nuance in LAWRS: when to show a gust as a separate value

• Why the single figure “21” matters to pilots and dispatchers

• A quick compare-and-contrast: 21 vs 17G21 vs 17G21 vs 21G (what you’ll see in practice)

• Practical takeaways: how to read wind groups in LAWRS-like reports

• Related weather tools that pair with gust reports (brief tangent)

• Bottom line: turning gust numbers into real-world decisions

Let’s break down the wind math

Weather reporting in aviation isn’t just about “the wind is 17 knots.” It’s about how that wind behaves. Gusts—the sudden bursts up to a higher speed—can change everything for a flight. Picture a small airplane lifting off in a gust and sensing a quick shove to the side. That moment matters. In a wind observation, you’ll typically see two pieces together: the steady, average wind and any gusts that spike above that average. The question many learners wrestle with is: when the gust speed is 21 knots and the two-minute average is 17, how is the gust shown in the report?

The scenario in focus

Suppose the wind observation shows a calm 17 knots average, but gusts reach 21 knots. In the context of the Limited Aviation Weather Reporting System (LAWRS), the key takeaway is simple: the gust value is the important number you’d report when the gusts are present. If you’re given a choice between different formats, the one that directly communicates the gust height is the right fit. In this case, the gust number to highlight is 21.

The notation nuance in LAWRS

Here’s where things get a little curious, and that curiosity matters for both reading and communicating wind data accurately.

• Gusts as a separate figure: In many LAWRS-style observations, when gusts are present, the gust speed can stand on its own as the explicit gust value. That’s the “21” you’d report to indicate gusts up to 21 knots, even if the average is 17.

• Average plus gust in one line: Some formats combine the two numbers, like writing 17G21, to show that the wind average is 17 knots and gusts peak at 21 knots. This format is common in other aviation weather reporting traditions, and it’s useful for quickly grasping both the baseline and the gust, but it isn’t always the required presentation in every LAWRS context.

• The tempting but less precise formats: You might see options that try to fuse the numbers into a single glyph or to place “G” in front of a gust speed. For instance, G21 is clear about gusts, but it omits the average speed. 17G is not about the gust alone; it still leaves the gust value hanging. And 21G would imply a gust but doesn’t anchor it to the base wind. Those can mislead if the observer or the system expects a two-part relationship (average plus gust) or a gust-focused note only.

So, why does the answer commonly come down to “21” in the specific LAWRS question you’re studying? Because the core message is: when the task is to indicate the gust itself, 21 communicates the gust speed directly. It removes ambiguity about the baseline wind and makes it crystal clear what peak gusts could feel like for the aircraft. Pilots and dispatchers can then quickly assess whether that gust is within acceptable limits for a takeoff, landing, or a staged approach to a runway. The number 21 becomes the actionable piece of data.

A quick compare-and-contrast you can carry in your head

• 21: You’re naming the gust speed alone. It’s straightforward and emphasizes the gust height without tying it to an average.

• 17G21: You’re showing both the baseline (17) and the gust (21). This is highly informative, but you must ensure the reporting system or the question’s format expects this combined presentation.

• 17G or G21 or 21G: Each has a use, but you should match the format to what the regulations or the reporting protocol specify. If the prompt asks for the gust itself, 21 is the crisp answer.

Why pilots care about gust numbers

Gusts aren’t just another line on a page. They affect climb performance, control sensitivity, and crosswind components. A gust can momentarily increase the crosswind push on a wing, influence the stall margin during approach, and change the runway lighting cue in a microsecond. For a pilot, knowing that gusts can reach 21 knots—even if the average wind is 17 knots—helps with decisions like selecting a runway with better crosswind tolerance, adjusting flap settings, or choosing an approach angle that keeps the airplane within stable limits.

If you’re curious about how this translates into real-world numbers, think of a takeoff attempt into gusty wind. The airplane’s airspeed stays fixed in the cockpit, but the wind adds or subtracts from ground speed and apparent wind. A gust to 21 knots is a significant bump that can affect lift timing, engine response (in some configurations), and how quickly you can stabilize the aircraft after liftoff. That’s why gust reporting isn’t just trivia—it’s a practical safety signal.

A small tangent about related weather tools

While LAWRS gets the spotlight here, pilots rarely rely on a single source for wind details. METARs—the routine aviation weather reports—often pair wind, gusts, visibility, and cloud conditions in compact blocks. For longer planning, TAFs (terminal aerodrome forecasts) carry forward-looking wind trends and gusts. Then you’ve got AWOS/ASOS systems, which feed real-time data to pilots and air traffic controllers. Together, these tools help you triangulate wind behavior across the takeoff corridor and final approach. If you’ve ever watched a pilot glance at the wind readout and nod, you’ve seen this dance in action: average speed gives the baseline, gusts shout out the volatility, and the crew uses that information to set up for a safe landing or takeoff.

Tips you can use when reading wind reports

• Always check whether the format presents the gust as a stand-alone value or as part of an average-plus-gust line. If the prompt asks for the gust itself, the number alone (like 21) is often the direct answer.

• Remember: gusts measure peak intensity. The average wind tells you the steady push; the gust is the temporary spike you need to anticipate.

• In practical planning, both pieces matter. A robust preflight check will consider the two-minute average for baseline performance and the gust value for margin during critical phases of flight.

• When in doubt, align with the reporting system’s standard. If the protocol emphasizes a separate gust figure, use the gust alone to communicate the gust strength. If it favors a combined format, be ready to interpret both numbers quickly.

A friendly wrap-up

Wind is a stubborn reminder that flight is an interplay of physics and timing. The gust reaching 21 knots, on a calm 17-knot average, is a signal that wind is not just a steady push—it’s dynamic, momentary, and consequential. In the LAWRS context you’re studying, the clearest way to convey that gust, when asked for the gust value itself, is simply 21. It’s tidy, decisive, and immediately useful for quick decision-making by pilots and ground crews alike.

If you’ve got a moment, consider how this small notation difference mirrors a broader truth in aviation communication: clarity saves cycles, and precision saves lives. The gust number isn’t just a digit on a sheet; it’s part of a safety net that keeps approaches smoother, landings steadier, and flights safer. And that’s the essence of good weather reporting—delivering the right information in a way that makes sense the moment you need it.

That’s all there is to it. The next time you see a wind observation with a 2-minute average of 17 knots and gusts up to 21, you’ll know what to focus on and how to interpret it. It’s a small, practical detail, but in aviation, those details add up to big difference-making moments in the sky.