Route Assessment Guide

Understanding how route conditions are evaluated and what the scores mean for your flight.

Overview

The Route Assessment tool analyzes weather conditions along your planned flight path and provides a simple score to help you understand what to expect. It combines real-time pilot reports, weather forecasts, and advisories to give you a clear picture of conditions for your specific route and altitude.

The assessment breaks your flight into three phases - takeoff, cruise, and landing - because conditions can vary significantly at different points along your journey. Each phase gets its own score, and these combine into an overall assessment for your flight.

Not sure where to start? See live scores for the 25 busiest US flight routes — the same assessment, pre-computed for the most popular city pairs.

Flight Phases

Your flight is evaluated in three distinct phases, each with its own geographic area and altitude range:

Takeoff Phase

The takeoff phase covers the area around your departure airport. This includes the climb-out from the runway to your cruising altitude. Weather conditions in this zone can affect your departure experience, including any bumps during the initial climb.

What this means for you: If you see hazards in the takeoff phase, you might experience some turbulence shortly after leaving the ground. Pilots are especially attentive during this critical phase and will adjust their climb profile if needed.

Cruise Phase

The cruise phase is the longest part of your flight, covering the route between the departure and arrival areas. This is when the aircraft is flying at its planned cruising altitude along a corridor between your origin and destination.

What this means for you: Most of your flight time is spent in the cruise phase, so conditions here have the biggest impact on your overall experience. The score for this phase considers how much of your route passes through areas with reported or forecast hazards.

Landing Phase

The landing phase covers the area around your destination airport. This includes the descent from cruising altitude down to the runway. Weather conditions at your arrival airport affect this phase.

What this means for you: Hazards in the landing phase mean you might feel some bumps as you descend toward your destination. This is a normal part of flying, and pilots are trained to handle varying conditions during approach.

How Phases Are Weighted

The overall score is a weighted average of the three phase scores. The weights are calculated based on the actual distance of each phase - so for a long cross-country flight, the cruise phase carries more weight, while for a shorter flight, the takeoff and landing phases have more influence. This ensures the score reflects what you will actually experience based on your specific route.

Form Options Explained

The route form lets you customize the assessment to match your specific flight. Here is what each option does:

Cruise Altitude

The flight level your aircraft will cruise at during the main portion of the flight. Commercial jets typically fly between FL300 (30,000 feet) and FL400 (40,000 feet). Different altitudes can have different weather conditions.

Impact on assessment: The assessment looks for hazards at and around your selected cruise altitude. Turbulence and other conditions often exist at specific altitude ranges, so the altitude you select affects which hazards are relevant to your flight.

Example: If there is turbulence forecast at FL350 but not at FL390, selecting a higher altitude would show a different assessment.

Airport Radius

The size of the circular area around each airport that defines the takeoff and landing phases. This controls how much airspace near the airports is considered when assessing departure and arrival conditions.

Impact on assessment: A larger radius captures more hazards near the airports but may include conditions you will not fly through. A smaller radius focuses on the immediate airport area but might miss relevant nearby weather.

Example: A 50nm radius covers approximately the first 10-15 minutes of flight, while 100nm covers more of the climb and descent.

Corridor Width

The width of the route corridor during the cruise phase. Aircraft do not fly a perfectly straight line - actual routes may deviate slightly due to air traffic control, winds, or weather avoidance.

Impact on assessment: A wider corridor captures hazards that are near but not directly on the route centerline. This gives a more conservative assessment. A narrower corridor shows only hazards very close to the direct route.

Example: A 50nm corridor means hazards within 25nm on either side of your route are considered.

Altitude Buffer

How far above and below your cruise altitude to look for hazards. Pilots may climb or descend to avoid turbulence, so conditions at nearby altitudes are relevant.

Impact on assessment: A larger buffer gives a more complete picture of conditions in your altitude range. A smaller buffer focuses only on hazards very close to your exact cruising level.

Example: With a ±2,000ft buffer at FL350, hazards between FL330 and FL370 would be included.

Live Flight Tracking

You can put a real flight on your assessment. Enter a flight number — either the airline form like DL2071 or the radio callsign form like DAL2071 — and Flight Chop finds the aircraft using live ADS-B transponder data. Its position, altitude, and growing trail appear on the route map, and its actual flown altitude is drawn over the planned profile so you can see exactly where the flight sits relative to the turbulence hazards, both laterally and vertically.

If you have already analyzed a route, tracking a flight never changes your airports — the live aircraft simply overlays your analysis. If you start from just a flight number, the published route for that flight number is looked up and used to fill the form, but only after the aircraft's live position confirms it: published route data is community-maintained and flight numbers get reassigned, so an entry the aircraft's actual position contradicts is rejected with a note instead of being analyzed as if it were true.

Once a route is analyzed, the map also shows corridor traffic: other aircraft currently aloft inside your corridor, at en-route altitude, heading the same direction. These are the flights experiencing your route right now. Click any of them to make it your tracked flight — no flight number typing required. A small toggle on the map hides the layer if you prefer a cleaner view.

Tracking survives a page refresh: the flight and its accumulated trail are restored for up to six hours, then automatically forgotten. Because ADS-B has no history service, the trail only contains positions received while you had the page open — after a long break it will jump from where it left off to the aircraft's current position.

Live aircraft data comes from the community-run adsb.lol network (open data, ODbL), with flight-number and airline lookups from adsbdb. Coverage depends on volunteer receivers, so the occasional gap or "signal stale" period is normal. The tracked flight is display-only — a flight-data outage never changes your turbulence score.

Understanding Scores

Each phase and the overall route receive a score from 1 to 10. Higher scores mean smoother expected conditions. Here is what each score range means:

Smooth

(Score: 9 - 10)

Minimal to no reported or forecast turbulence in this phase. Expect a comfortable flight with little to no noticeable bumps.

What to expect: You can relax and enjoy the flight. Any movement will be barely perceptible.

Light Bumps

(Score: 7 - 9)

Some light turbulence reported or forecast. This is very common and nothing to worry about.

What to expect: You might notice occasional gentle bumps, similar to driving over minor road imperfections. Beverage service continues normally.

Bumpy

(Score: 5 - 7)

Moderate conditions reported or forecast along portions of the route. The aircraft will handle this without any problems.

What to expect: Expect noticeable bumps during parts of the flight. Flight attendants may pause service temporarily. Keep your seatbelt fastened.

Rough

(Score: 3 - 5)

Significant turbulence reported or forecast. Pilots will work to minimize your exposure by changing altitude or route if possible.

What to expect: You will likely feel definite bumps. The fasten seatbelt sign will probably be on for extended periods. The aircraft remains safe.

Very Rough

(Score: 1 - 3)

Severe conditions reported or forecast along the route. This is uncommon and pilots take it very seriously.

What to expect: If conditions are this severe, pilots will likely reroute or change altitude significantly. Expect the crew to prioritize safety and comfort.

What Affects Your Score

The assessment considers multiple types of weather information. How much each one lowers the score depends on its severity, whether pilot reports confirm it, and how avoidable the hazard type is in practice — not simply on which kind of advisory it is. Learn more about each type in the Weather Alerts guide.

Pilot Reports (PIREPs)

Observed conditions

Real-time reports from pilots who have just flown through an area. These are the most current and accurate source of actual conditions — they raise the score impact of nearby stretches directly and confirm (or soften) forecast advisories.

SIGMETs

Severe forecasts

Significant meteorological warnings issued for severe hazards like strong turbulence or thunderstorms. Because they describe severe conditions, stretches they cover take a large score reduction.

G-AIRMETs

Broad forecasts

Graphical forecasts for less severe but still significant conditions. These cover broader areas and are updated regularly.

Center Weather Advisories

Short-term forecasts

Short-term forecasts from air traffic control centers about developing conditions. These help identify areas that may become problematic.

Additional Factors Considered

Severity: More severe conditions have a bigger impact on the score than light conditions.
Recency: Recent pilot reports are weighted more heavily than older ones, since conditions change.
Coverage and duration: The route is scored stretch by stretch, so the score reflects how much of your flight is actually affected — and it separately weighs the roughest sustained stretch, so a genuinely rough section is never averaged away by hours of smooth air.
Altitude relevance: Only hazards at altitudes you will actually fly through are considered.
Overlapping advisories: Each stretch of your route is scored once, by the single most impactful advisory or report covering it. When advisories overlap (for example, a CWA issued inside a SIGMET), the same weather is never counted twice.
Avoidability: Thunderstorms are visible on radar and crews routinely deviate around them, so isolated or scattered storm areas weigh a little less than their coverage suggests. Embedded storms, squall lines, clear-air turbulence, and mountain wave cannot be avoided the same way and keep full (or extra) weight.

Interpreting Results

Look at individual phases: The overall score is helpful, but checking each phase tells you when during the flight you might encounter bumps.
Check the hazard list: Each phase shows what specific conditions were found. This helps you understand why a score is what it is.
Consider coverage: A hazard covering 10% of your route has less impact than one covering 50%. The coverage percentage is shown for polygon-based hazards.
Conditions change: Weather is dynamic. Check again closer to your flight time for the most current assessment.

Remember that this tool uses the same data sources pilots and dispatchers use. A lower score does not mean your flight is unsafe - it means there are reported or forecast conditions that could cause bumps. Pilots are trained to manage these situations, and they may adjust altitude or route to minimize turbulence when possible.

Try Route Assessment

Enter your origin and destination to get a phase-by-phase turbulence score for your flight.