What is a good weather score for challenging flying?

Scores above 250 are labeled "Gnarly" and provide a meaningful challenge. Above 300 is "Nasty" with serious weather. Above 400 is "Wicked" — multiple severe phenomena stacking together. Even scores around 150 ("Soggy") offer interesting conditions.

Where does the weather data come from?

All METAR and TAF data is sourced from AviationWeather.gov, which is run by NOAA's Aviation Weather Center. This is the same data source that MSFS 2024, MSFS 2020, and X-Plane use for live weather rendering.

How often are weather scores updated?

METAR observations are issued every 30-60 minutes at most airports, with special reports (SPECIs) issued when conditions change significantly. Our route cache refreshes every 15 minutes to balance freshness with performance.

Why do older METARs get lower scores?

A METAR from 2 hours ago may not reflect current conditions. We apply a recency penalty: no penalty within 30 minutes, 10% reduction at 1 hour, 25% at 1.5 hours, 50% at 2 hours, and 75% beyond that. This ensures routes reflect current weather, not stale data.

Shit Weather

The Scoring System

How METAR data becomes a weather severity score.

How It Works

Every airport's weather score is calculated from its real-time METAR observation. The score is additive — each weather factor contributes points, and they stack. A thunderstorm with low visibility and gusty crosswinds scores much higher than any single factor alone.

For route pairs, the origin airport uses its current METAR score, and the destination uses a TAF (Terminal Aerodrome Forecast) when available for a forward-looking prediction. The combined score is the sum of both, ranked worst-first.

Weather Phenomena

Points awarded based on METAR weather condition codes. Multiple phenomena stack.

Severe

250

FC — Funnel cloud

200

TS — Thunderstorm

150

FZ — Freezing

100

GR — Hail

Moderate

+RA/+SN — Heavy

FG — Fog

RA/SN — Rain/Snow

BR — Mist

Light

DZ — Drizzle

+50

+ — Heavy intensity

Visibility

Scored based on reported visibility in statute miles. Lower visibility = higher score.

≤0.5 statute miles

≤1 statute mile

≤3 statute miles

≤6 statute miles

Sky Conditions

Cloud coverage, ceiling height, and dangerous cloud types all contribute to the score.

Ceiling Height

≤200 ft AGL

≤500 ft AGL

≤1,000 ft AGL

≤2,000 ft AGL

≤5,000 ft AGL

Cloud Coverage

OVC — Overcast

BKN — Broken

SCT — Scattered

FEW

Cloud Types

100

CB — Cumulonimbus

TCU — Towering Cumulus

Wind & Crosswind

Wind speed and gusts are scored separately from the crosswind component, which is calculated against each airport's best-aligned runway.

Wind Speed

≥25kt sustained 40

≥15kt sustained 20

≥40kt gusts 30

≥30kt gusts 20

Crosswind Component

≥25kt crosswind 80

≥20kt crosswind 60

≥15kt crosswind 40

≥10kt crosswind 25

Recency & Trend Adjustments

Raw scores are adjusted for data freshness and forecast trends before being used in route ranking.

METAR Age Penalty

Older observations are less reliable, so their scores are reduced.

100%

≤30 min

90%

≤60 min

75%

≤90 min

50%

≤120 min

25%

>120 min

TAF Weather Trend

Destination airports use TAF forecasts when available. We analyze the trend over the next 3 hours and adjust the destination score accordingly.

1.0x

Worsening

1.0x

Stable

0.6x

Improving

If the TAF shows weather improving to less than half the current score within 3 hours, the destination score is reduced by 40%. This deprioritizes routes where the weather will clear before you arrive.

Severity Labels

Route scores are categorized into severity levels for quick reference.

Wicked

400+ pts

Nasty

300–399 pts

Gnarly

250–299 pts

Crummy

200–249 pts

Soggy

150–199 pts

Drizzly

<150 pts

All weather data sourced from AviationWeather.gov (NOAA's Aviation Weather Center) — the same data MSFS 2024, MSFS 2020, and X-Plane use for live weather.

Want to explore all weather conditions?

See the Worst Weather Now

Questions?

What is a good weather score for challenging flying?: Scores above 250 are labeled "Gnarly" and provide a meaningful challenge. Above 300 is "Nasty" with serious weather. Above 400 is "Wicked" — multiple severe phenomena stacking together. Even scores around 150 ("Soggy") offer interesting conditions.
Where does the weather data come from?: All METAR and TAF data is sourced from AviationWeather.gov, which is run by NOAA's Aviation Weather Center. This is the same data source that MSFS 2024, MSFS 2020, and X-Plane use for live weather rendering.
How often are weather scores updated?: METAR observations are issued every 30-60 minutes at most airports, with special reports (SPECIs) issued when conditions change significantly. Our route cache refreshes every 15 minutes to balance freshness with performance.
Why do older METARs get lower scores?: A METAR from 2 hours ago may not reflect current conditions. We apply a recency penalty: no penalty within 30 minutes, 10% reduction at 1 hour, 25% at 1.5 hours, 50% at 2 hours, and 75% beyond that. This ensures routes reflect current weather, not stale data.

Pick Your Poison

Explore More

Thunderstorms

Active CB clouds, heavy precipitation, and convective chaos.

Low Visibility

IFR and LIFR conditions. Fog, mist, and near-zero visibility.

Crosswinds

Gusty approaches and strong crosswind components on landing.

Blizzards

Snow, ice, freezing precipitation, and winter whiteouts.