Understanding how 5/8 cloud cover at 10,000 feet AGL is encoded in LAWRS column 10.

Outline:

• Opening that sets the scene: cloud codes in aviation weather, why they show up in LAWRS-style reports, and how pilots use them in real life.

• Clear, plain-language explanation of cloud coverage codes (FEW, SCT, BKN, OVC) and the octas scale.

• How the altitude field works: the number after the coverage code is the cloud base in hundreds of feet AGL.

• The specific example: why 5/8 coverage equals BKN and why the base at 10,000 ft is written as 100.

• A quick contrast with SCT100, OVC100, CLR100 to reinforce understanding.

• Why these codes matter for flight planning and safety: effects on visibility, icing potential, and approach minima.

• A light digression with relatable analogies to make the numbers stick.

• Practical tips and a concise recap.

• Friendly closing thought linking to further learning.

Cloud codes you’ll actually see in LAWRS-style notes

Let’s face it: meteorology can feel like learning a new language. But the cloud-coverage codes are one of the friendlier dialects. In aviation weather reporting, pilots and dispatchers rely on short, standardized terms to answer a single question fast: How much of the sky is cloudy right now? The answer comes in two parts—the amount of the sky covered by clouds and the height of the cloud base above the ground. The first part uses a little octa-scale, the second uses a height in hundreds of feet. Put together, they paint a quick picture of what a pilot might expect when taking off, flying the route, or landing.

The octas scale: FEW, SCT, BKN, OVC

Think of the sky as a pizza sliced into eight equal pieces. Each “slice” is an eighth of the sky. The codes map to how many slices are shaded with clouds:

• FEW = 1-2 octas (1/8 to 2/8) — a thin veil of cloud

• SCT = 3-4 octas (3/8 to 4/8) — scattered clouds

• BKN = 5-7 octas (5/8 to 7/8) — broken clouds (you can feel it when the sky looks noticeably cloudy)

• OVC = 8 octas (8/8) — overcast, absolutely covered

Notice how the numbers aren’t arbitrary. They line up with real-world observations of how much of the sky is blocked by clouds. Scientists and pilots alike lean on this shorthand because it’s fast, consistent, and easy to verify from multiple observers.

The altitude string: base height in hundreds of feet AGL

After the coverage term, you’ll often see a three-digit number. That number isn’t the atmospheric pressure, and it isn’t a speed limit. It’s the cloud base height, expressed in hundreds of feet above ground level (AGL). So:

• 100 = the base is at 10,000 feet AGL

• 040 would be 4,000 feet AGL

• 060 would be 6,000 feet AGL

This pairing—coverage word plus base height—lets a pilot answer two critical questions at a glance: “How much sky is cloudy where I’ll be flying?” and “From what altitude does that cloud cover begin?”

The big example: 5/8 of the sky at 10,000 feet AGL

Okay, let’s break down the specific scenario you asked about: 5/8 coverage at 10,000 feet AGL encoded in column 10.

• Coverage: 5/8 falls squarely into the “broken” category. That’s the official interpretation: between 5/8 and 7/8 of the sky is cloud-covered. So FEW and SCT don’t fit this scenario—those would be lighter on the coverage side.

• Height: 10,000 feet AGL is written as 100 in the column. The rule of thumb is simple: a two- or three-digit number after the coverage term is the base height in hundreds of feet. Thus, 100 means 100 × 100 feet = 10,000 feet.

Put those together and you get BKN100. It communicates both the extent of cloud cover (broken clouds, 5/8 to 7/8) and the cloud base (10,000 feet AGL). That crisp combo is exactly what pilots need, especially when planning climbs, descents, and approach procedures.

Why not the other choices?

A quick contrast helps lock the idea in:

• SCT100 would mean scattered clouds at 10,000 feet. That implies a lighter cloud coverage (3/8 to 4/8), not the 5/8 scenario.

• OVC100 would mean overcast with the entire sky cloud-covered at the same 10,000-foot base. That would be an extreme where you’d expect more significant limitations.

• CLR100 would signal a clear sky with no meaningful cloud cover, which isn’t accurate if we’re quantifying 5/8 coverage.

Real-world significance: why this matters

Cloud coverage and cloud base aren’t just trivia for a METAR column; they shape decisions in the cockpit. A sky with 5/8 to 7/8 cloud cover at 10,000 feet AGL has several practical implications:

• Flight levels and routes: If you’re cruising near or above 10,000 feet, a BKN100 condition tells you where the cloud layer begins. It helps with planning transitions through the layer, choosing altitudes with the least turbulence, and anticipating potential icing if you’re in the right temperature band.

• Visibility and weather phenomena: Broken clouds can coincide with reduced visibility at the surface or in the layer beneath the cloud deck. It also implies the possibility of embedded precipitation or a convective pattern developing below the base.

• Approach minima: For pilots on approach, the cloud base and coverage affect decision altitude and whether a continued approach is feasible without radar or instrument guidance. Ground observers will rely on these codes to set safe expectations for winds, ceilings, and visibility.

A little analogy that sticks

Let’s try a simple analogy to help these numbers stick in memory. Imagine you’re standing at the bottom of a multi-story building, wanting to know how many floors above you the ceiling is, and how many floors are blocked by fog. The coverage code is like the level of fog on the sky-level playground—how much of the horizon is hidden. The height code is the actual number of floors you’d have to climb to reach the cloud base. If you see BKN100, it’s as if about five to seven floors are shrouded, and the first ceiling is at roughly ten stories up. The picture forms quickly, even if you’re on the ground juggling flight plans and fuel calculations.

Common traps and quick tips

• Don’t mix up the numbers with a different unit. The height is in hundreds of feet AGL, not in feet or miles. So 100 means 10,000 feet, 040 would be 4,000 feet, etc.

• Remember the coverage mapping: FEW = 1-2 octas, SCT = 3-4 octas, BKN = 5-7 octas, OVC = 8 octas. If you’re in doubt, count the “visible slices” in the sky and map them to octas.

• When you see a column that combines coverage and height, treat it as a compact weather message that you’ll translate into flight planning actions. It’s not just trivia; it’s a practical signal for safety-first decisions.

• If you ever hear or see an example that uses different wording, translate it into the octas-plus-height framework. It’s a reliable compass for understanding.

A few more notes to broaden your perspective

• These codes aren’t unique to one system. They’re widely used in METARs, TAFs, and LAWRS-type reports across many regions. The consistency helps crews and dispatchers communicate quickly, even when languages differ.

• Cloud base information isn’t the only thing you’ll see in column 10. Some reports add temperature-dew point, wind, and visibility in nearby fields. The more you practice, the easier the pieces click together.

• Weather is dynamic. A forecast can say “BKN100” now, but by the time you reach the area it could be changing to SCT or even OVC. That’s why pilots keep a running weather picture and plan contingencies.

Quick recap for mental anchors

• 5/8 cloud coverage = BKN (broken)

• Height 10,000 feet AGL = 100 (hundreds of feet)

• Combined: BKN100 means broken clouds with base at 10,000 feet AGL

• SCT100 would be lighter (scattered) coverage at the same base

• OVC100 means a fully cloud-covered sky at the same base

• CLR100 signals clear skies—no significant cloud presence

Final thought: turning codes into confident decision-making

The beauty of these codes lies in their economy. A single line can convey a lot of actionable information. When you’re up there in the cockpit or planning a route on the ground, you want signals that are precise, not guesswork. The BKN100 shorthand is one of those signals—clear enough to guide decisions, compact enough to fit on a single communication line, and reliable enough to keep you focused on the task at hand.

If you’re curious to deepen your familiarity, look for examples in real-world METARs and LAWRS-style summaries. Notice how the clouds show up in different airports, how the base heights shift with altitude zones, and how crews adjust their plans as the ceiling changes. The more you see, the more natural these codes become—like learning to read a weather map with your eyes half-closed, but your instincts fully awake.

And that’s the essence: a straightforward rule set that translates quickly into safer, smoother flights. BKN100 isn’t just a code; it’s a snapshot of the sky you can trust—and plan around.