WX Score — How It Works
Understand how PlaneWX calculates your score, what triggers an unfavorable status, and how your personal minimums shape the assessment.
Overview
Your WX Score starts at 100 points and is reduced by deductions for weather conditions that don't meet your personal minimums and aircraft capabilities. It is not based on generic VFR/IFR standards — it reflects what matters for your flight, your aircraft, and your experience level.
Favorable — Conditions meet your minimums. Plan confidently.
Caution — Some conditions are close to your limits. Monitor closely.
Marginal — Multiple concerns present. Consider alternate times or routes.
Unfavorable — Conditions exceed your limits. Strongly consider postponing.
Automatic Unfavorable Conditions
Certain conditions are always unfavorable regardless of your score math. These are hazards that no personal minimums setting can mitigate:
Freezing Precipitation
- • Freezing rain (FZRA)
- • Freezing drizzle (FZDZ)
- • Freezing fog (FZFG)
- • Ice pellets (PL)
Unfavorable regardless of FIKI equipment
Convective Weather
- • Thunderstorms (TS, TSRA, TSGR)
- • Vicinity thunderstorms (VCTS)
- • Hail (GR)
- • Squalls (SQ)
Severe Hazards
- • Funnel cloud / tornado (FC)
- • Volcanic ash (VA)
- • Severe dust/sand storms (+DS, +SS)
Personal Limit Exceedances
- • Ceiling below your hard limit
- • Visibility below your hard limit
- • Crosswind exceeds your limit (all runways)
- • Icing exceeds your tolerance
- • Turbulence exceeds your tolerance
- • Any icing without FIKI equipment
The 12-Hour Rule
PlaneWX treats flights differently based on how far out they are. TAFs (Terminal Aerodrome Forecasts) are highly reliable within 12 hours but become uncertain beyond that.
Within 12 Hours
- Server-side pre-flight check runs against TAF data
- Hard limit exceedances = 0% score
- Hazardous weather phenomena = 0% score
- Comfort/limit zones checked with graduated penalties
- Server handles turbulence, icing, crosswind, and wind shear scoring
Beyond 12 Hours
- AI-only scoring (pre-flight check skipped)
- No automatic 0% — minimum floor of 25%
- Forecasts are uncertain — conditions may improve
- Briefing auto-refreshes and re-scores as departure approaches
- AI scores icing and turbulence based on your personal limits
Why 25% and not 0%? Forecasts more than 12 hours out are based on models (GFS, NBM) and area forecasts (AFDs), which are less precise than TAFs. A 0% score would suggest certainty that doesn't exist. The 25% floor signals "unfavorable but uncertain" — your briefing will automatically re-score with more accurate data as departure approaches.
Scoring Categories & Maximum Deductions
Each weather category has a maximum deduction cap. No single factor can take more than its cap, and the system validates this server-side.
| Category | Max Points | When It Applies |
|---|---|---|
| Ceiling below minimums | -40 | Forecast ceiling at departure or arrival is below your hard limit |
| Visibility below minimums | -40 | Forecast visibility at departure or arrival is below your hard limit |
| Icing (no FIKI) | -40 | Any forecast icing without FIKI equipment |
| Icing (exceeds limit) | -15 to -50 | Severity exceeds your stated icing tolerance (even with FIKI) |
| Icing (within limit) | -5 | Icing at or below your tolerance — caution only. Severity derived from multi-model analysis (HRRR + NAM + GFS) |
| Severe icing | -50 | Severe icing exceeds any pilot limit |
| SLD risk ≥40% (CIP nowcast) | NO-GO | CIP has high confidence SLD is present. No aircraft — including FIKI — is certified for SLD (Appendix O). FIKI does not mitigate SLD. |
| SLD risk 10–39% (CIP nowcast) | -10 to -30 | 10–19%: −10 pt · 20–29%: −20 pt · 30–39%: −30 pt. Applies to all aircraft regardless of FIKI. Only scored within ~2 hours of departure when CIP nowcast is active. |
| Thunderstorms | -40 | Forecast during your flight window (TAF TEMPO/FM) |
| Convective SIGMET | -50 | Active convective SIGMET valid during your flight |
| Turbulence (exceeds limit) | -10 to -30 | Severity exceeds your stated turbulence tolerance |
| Turbulence (within limit) | -5 | Turbulence at or below your tolerance — caution only |
| Crosswind | -15 | Server-calculated from TAF wind + runway data (within 12h) |
| Headwind impact | -5 to -15 | Flight time increased 15-25% (-5), 25-40% (-10), >40% (-15) |
| SIGMET (non-convective) | -15 | Active SIGMET along your route |
| G-AIRMET (IFR / MTN OBSCN) | -10 | IFR conditions or mountain obscuration along your route |
| Mountain obscuration (VFR) | -50 | G-AIRMET Sierra MTN OBSCN directly on your VFR route |
| Approaching minimums | -10 | Ceiling within 500 ft or visibility within 1 SM of your limit |
| Wind shear | -15 | Graduated penalty based on your wind shear speed limits |
| Density altitude | -15 | High density altitude affecting aircraft performance |
Comfort vs. Limit (Soft / Hard Minimums)
PlaneWX uses a two-tier minimums system for graduated scoring:
Comfort (Soft Limit)
Your preferred conditions. Exceeding your comfort level puts you in the caution zone (yellow). The score penalty is proportional to how far into the zone you are.
Example: Ceiling comfort 2000 ft, limit 1000 ft. A 1500 ft ceiling is in the caution zone.
Limit (Hard Limit)
Your absolute maximum tolerance. Exceeding your limit is unfavorable (red). Within 12 hours, the score drops to 0%. Beyond 12 hours, the 25% floor applies.
Example: Ceiling limit 1000 ft. A 900 ft ceiling is unfavorable.
At your limit = caution, not unfavorable. If you set your turbulence limit to "Moderate" and the forecast shows moderate turbulence, that's a -5 caution — not unfavorable. You set that limit because you accept it. Unfavorable only triggers when conditions exceed your stated limit.
How Aircraft & Profile Affect Your Score
FIKI Equipment
Aircraft with FIKI (Flight Into Known Icing): moderate icing within your limit = -5 caution. Aircraft without FIKI: any forecast icing = -40 unfavorable.
Aircraft Overrides
Aircraft-specific limits (crosswind, turbulence, icing) override your personal minimums. The more restrictive value always wins. Aircraft overrides are shown with a plane icon () in the Personal Minimums bar.
Flight Rules
VFR and IFR flights use separate ceiling/visibility minimums from your profile. VFR flights also check for mountain obscuration (G-AIRMET Sierra) along the route.
What Does NOT Affect Your Score
PlaneWX is strict about only deducting for confirmed, product-backed conditions. These items are mentioned in your briefing for awareness but do not reduce your score:
- ✓Forecast uncertainty or distance to departure
- ✓Regional patterns without product confirmation (e.g., "gusty winds on ridges")
- ✓Expired TEMPOs, G-AIRMETs, or SIGMETs that end before your flight
- ✓Old PIREPs that won't persist to departure time
- ✓Sky cover percentage alone (OVC ≠ low ceiling without a height value)
- ✓Temp/dewpoint spread or fog risk (awareness only unless visibility is below minimums)
- ✓NBM gust forecasts (no wind direction = can't calculate crosswind)
- ✓Thunderstorm mentions in WPC outlooks at 3+ days (scored as caution, not unfavorable)
Score Breakdown & Validation
- • Click Score Breakdown in your briefing to see exactly which factors are deducting points
- • Server-side validation ensures no single category exceeds its deduction cap
- • If a briefing section is marked "marginal" or "unfavorable" but has no matching deduction, the system adds one automatically
- • The WX Score is cross-checked against the Personal Minimums Check for consistency
- • For flights within 12 hours, the pre-flight check results take precedence over AI scoring