How to Read Met Office F214 and F215 Aviation Weather Charts
- Aug 3
- 10 min read
Updated: Aug 10
The Met Office F214 and F215 charts can look dense when you first meet them. Each page compresses a large part of the weather picture into a format designed for practical flight planning. Once you learn the reading order, the codes begin to form a useful three-dimensional view of the atmosphere along your route.
The F214 tells you how the forecast wind and temperature change with altitude. The F215 shows the significant weather below 10,000 ft, including visibility, cloud, fronts, icing, turbulence and the freezing level. Used together, they help you answer two different questions: what will the air mass do to your aircraft, and what conditions might you meet while flying through it?
This guide uses real F214 and F215 examples dated 29 July. Treat the values as worked examples only. For a flight, obtain the current products and complete a full weather briefing.
Contents
Where to get F214 and F215 charts
The current official source is the Met Office Aeronautical Visualisation Service, known as MAVIS. The Met Office launched MAVIS as the replacement for its former aviation briefing platforms. You can register for access, open the reports area and download F214 and F215 products in PDF format for offline use or printing.
The F214 is the UK low-level spot wind chart. It provides forecast wind direction, wind speed and temperature at fixed latitude and longitude points and at several altitudes.
The F215 is the UK low-level significant weather chart. It covers the surface to 10,000 ft across the British Isles and the near Continent. It combines a map of fronts and weather areas with a table describing the conditions inside each area.
Both products are issued four times a day. Always confirm the issue time and validity before using the data, especially if you downloaded a chart earlier or saved it on a device.
Start with the times at the top
Reading the timing information first prevents a beautifully decoded chart from being applied to the wrong part of the day.
The example F214 says it was produced at `291050 UTC`. This means 1050 UTC on the 29th day of the month. Its main forecast is for 1800 UTC on 29 July and it is valid between 1500 and 2100 UTC.
That gives you three distinct ideas:
produced at: when the chart was generated;
forecast for: the central or fixed forecast time;
valid between: the period in which the forecast should be used.
The example F215 is valid from `291400` to `292300 Z`, meaning 1400 to 2300 UTC on the 29th. Its fronts and zones are valid at `291800 Z`, so the map is a snapshot of their expected positions at 1800 UTC. The table describes the forecast conditions across the longer validity period.
If a front is moving, its position at the beginning and end of the validity period will differ from the fixed-time snapshot. The movement arrows and speeds help you think through that change.
How to read the F214 spot wind chart
The F214 is organised as a geographical grid. Each box is headed by a latitude and longitude, such as `55N 00E` or `5230N 0230W`. The values inside apply to that forecast spot.
Each data row contains four items in a fixed order:
`altitude | wind direction | wind speed | temperature`
The altitude is expressed in thousands of feet above mean sea level. The wind direction is degrees true, the speed is knots and the temperature is degrees Celsius.
A worked F214 decode
Look at the `50N 0230W` box in the supplied chart. The row for 5,000 ft reads:
`05 240 20 +17`
This decodes as:
`05`: 5,000 ft AMSL;
`240`: wind from 240 degrees true;
`20`: wind speed 20 kt;
`+17`: forecast temperature +17°C.
The 2,000 ft row reads `02 280 15 +17`. At that level the forecast wind is from 280 degrees true at 15 kt, with a temperature of +17°C.
The two rows already reveal useful vertical change. Between 2,000 and 5,000 ft, the wind backs from 280 to 240 degrees and increases by five knots, while the forecast temperature remains +17°C. A route flown at the higher level would therefore require a different heading correction and groundspeed calculation.
Choose the right spot and level
Your route will rarely pass directly through a printed spot. Find the boxes around the route and compare them. A large change between neighbouring boxes can matter as much as the value in the nearest box, especially near a front or a strong pressure gradient.
Select the altitude closest to your planned cruising level, then inspect the rows above and below it. This shows whether a small altitude change could produce a useful tailwind, an awkward headwind, stronger drift or a marked temperature change.
Use the wind direction as true when working with a chart-based track. Keep your conversion between true and magnetic references consistent throughout the navigation calculation.
What the F214 can tell you in practice
The chart supports several planning tasks:
selecting a practical cruising altitude;
calculating heading, groundspeed and estimated time en route;
anticipating drift near controlled-airspace boundaries;
estimating the effect of wind on fuel planning;
spotting wind shear between the listed levels;
checking temperatures relevant to performance and icing awareness.
The values are forecasts for defined spots and levels. Terrain, convection and local effects can produce different conditions. Compare the F214 with the broader synoptic situation and the rest of the briefing.
How to read the F215 significant weather chart
The F215 has two linked parts. The map on the left divides the forecast area into lettered zones. The table on the right describes visibility, weather, cloud and the zero-degree isotherm in each zone.
Read it in this order:
confirm the validity period and fixed time;
trace your route across the map;
note every main zone and sub-zone it enters;
read the matching table rows from left to right;
check the outlook and any amendments.
Worked F215 decode: Area A
Area A is a good example because its general forecast is straightforward, while several local qualifications introduce much poorer conditions. Read each of the three columns across the same Area A row.
The first line, `30 KM NIL`, gives the broad background: 30 km visibility and no significant weather. The remaining lines describe exceptions within Area A:
`ISOL (OCNL A1) 7 KM SHRA/(RA FRONTS)`: isolated rain showers with 7 km visibility, becoming occasional in sub-area A1, with rain around fronts;
`ISOL 4000 M SHRA/RADZ MAINLY FRONTS`: isolated reductions to 4,000 m in rain showers or rain and drizzle, mainly near fronts;
`ISOL 3500 M +SHRA A1`: isolated visibility of 3,500 m in heavy rain showers within A1;
`ISOL 3000 M +TSRA OCCLUSION NW A1`: isolated visibility of 3,000 m in thunderstorms with heavy rain near the occlusion in the north-west of A1;
`ISOL HILL FG`: isolated hill fog, implying visibility below 200 m over affected high ground.
The cloud box adds the vertical structure and hazards:
`OCNL BKN/OVC AC ... 070/XXX`: occasional broken or overcast altocumulus with a base around 7,000 ft and tops above 10,000 ft, accompanied by the moderate icing and turbulence symbols shown on the chart;
`ISOL EMBD CB 015-035/XXX ... OCCLUSION NW A1`: isolated embedded cumulonimbus with bases between 1,500 and 3,500 ft and tops above 10,000 ft near the occlusion in north-west A1;
`SCT/BKN (OCNL OVC) CU SC ... 015-035/050-070 (LCA XXX A1)`: scattered or broken, occasionally overcast, cumulus and stratocumulus with bases between 1,500 and 3,500 ft and tops between 5,000 and 7,000 ft, locally extending above 10,000 ft in A1;
`ISOL SCT/BKN ST 007-010/015`: isolated scattered or broken stratus with bases between 700 and 1,000 ft and tops around 1,500 ft.
The final box reads `050-070 NW` and `070-090 SE`. The zero-degree isotherm is forecast between 5,000 and 7,000 ft in the north-west of Area A, rising to between 7,000 and 9,000 ft in the south-east. When visible moisture is present, compare these levels with your intended altitude and the icing information in the cloud box.
Fronts, zones and movement
The example map contains areas A, B, C and D, plus sub-areas A1 and B1. A sub-area identifies a local variation within a larger weather zone. If your route crosses A1, read the general Area A description and then apply the A1 qualifications.
Standard frontal symbols show warm fronts, cold fronts and occlusions. An arrow and speed describe movement. `15 KT` means the feature is expected to move at 15 kt. `SLOW` generally indicates a movement speed below five knots.
Scalloped boundaries divide areas with distinct weather. Their location matters because a short route can cross several forecast regimes. Mark the points where your route enters a new zone before decoding the table.
Surface visibility and weather
The first table column after the area letter is headed `SURFACE VIS AND WX`. Visibility is written in kilometres or metres, and the weather uses familiar METAR-style abbreviations.
In Area A, the first line reads `30 KM NIL`, giving a general forecast of 30 km visibility with no significant weather. The following lines introduce local deteriorations. These include isolated or occasional showers, rain around fronts, lower visibility in heavier showers, thunderstorms near the occlusion in north-west A1 and isolated hill fog.
Coverage words are important:
`ISOL`: isolated;
`OCNL`: occasional;
`WDSPR`: widespread;
`LCA`: locally;
`MAINLY FRONTS`: chiefly associated with fronts.
Precipitation intensity uses a prefix. A minus sign means light, no sign means moderate and a plus sign means heavy. Common weather groups include `RA` for rain, `DZ` for drizzle, `SH` for showers, `TS` for thunderstorm, `BR` for mist and `FG` for fog. Groups can be combined, so `+TSRA` describes a thunderstorm with heavy rain.
Hill fog deserves particular attention on a VFR route. On the F215 it implies cloud covering high ground and surface visibility below 200 metres in the affected hills. The surrounding lowland visibility can look acceptable while the route across rising terrain becomes unsuitable.
Cloud base, cloud top and amount
The cloud column follows the same zone structure. Cloud amount is shown as:
`FEW`: one to two oktas;
`SCT`: three to four oktas;
`BKN`: five to seven oktas;
`OVC`: eight oktas.
Cloud types follow the amount. Examples include `ST` for stratus, `SC` for stratocumulus, `CU` for cumulus, `AC` for altocumulus and `CB` for cumulonimbus.
Heights appear in hundreds of feet AMSL. A group such as `015-035 / 050-070` describes one range of cloud bases from 1,500 to 3,500 ft and tops from 5,000 to 7,000 ft. The precise reading depends on the cloud group and qualifications immediately before it.
`XXX` means the cloud top is above the chart's 10,000 ft upper limit. `EMBD CB` means embedded cumulonimbus, a serious concern because surrounding cloud can hide the cell from visual detection.
F215 cloud heights use mean sea level. Subtract terrain elevation to estimate clearance above the ground. This differs from TAF and METAR cloud bases, which are referenced to the reporting aerodrome.
Icing and turbulence symbols
The chart key at the lower left identifies the moderate and severe icing and turbulence symbols. These appear alongside affected cloud groups or areas of mechanical turbulence.
Read the symbol together with the cloud extent and base/top figures. It tells you where the hazard is forecast within the vertical structure, which is far more useful than a general statement that icing or turbulence may exist somewhere in the region.
A forecast of cumulonimbus or thunderstorm implies severe turbulence and icing. Give those areas generous clearance and use current observations, radar, SIGMETs and operational guidance to refine the plan.
The zero-degree isotherm
The final column is headed `0 C`. It gives the forecast height of the zero-degree isotherm, also called the freezing level, in hundreds of feet AMSL.
For Area A in the example, the freezing level is `050-070 NW` and `070-090 SE`. This means 5,000 to 7,000 ft in the north-west of Area A and 7,000 to 9,000 ft in the south-east.
The freezing level helps you judge where icing becomes possible when visible moisture is present. Temperature at exactly zero is only part of the assessment. Cloud type, precipitation, the icing symbols, the aircraft's equipment and the escape options all belong in the decision.
Unusual F215 codes worth recognising
Some groups appear less often in basic training examples and can slow down a real briefing. The supplied chart contains several useful examples.
`RADZ` combines rain and drizzle. `+SHRA` means heavy rain showers. `EMBD CB` means cumulonimbus embedded in other cloud. `LCA BASE` means the stated lower base occurs locally. `SEA WINDWARD COT` points to conditions on a windward coast. `UPSLOPES` identifies a terrain-related effect on slopes facing the airflow.
`OCCLUSION NW A1` narrows a condition to the occlusion in the north-west of sub-area A1. Read every qualifier because it controls where the hazard applies.
The outlook line at the bottom summarises the expected development beyond the main validity period. In the example, isolated fog is forecast locally from 2300 UTC, with other conditions broadly similar. Use a newer full briefing when the planned flight approaches or extends into the outlook period.
Build one weather picture from both charts
The F214 and F215 complement each other. Suppose the route crosses Area A at 5,000 ft near 50N 0230W. The F214 gives a forecast wind from 240 degrees true at 20 kt and a temperature of +17°C. The F215 adds the expected visibility, weather zones, cloud layers, convective hazards and freezing level.
That combined view can change the plan. A favourable wind at 5,000 ft has limited value if broken cloud, embedded cumulonimbus or a low freezing level makes the level unsuitable. Equally, good visibility beneath a cloud layer still requires a realistic drift, groundspeed, fuel and airspace calculation.
Continue the briefing with current METARs and TAFs along the route and at alternates, relevant SIGMETs, rainfall and satellite imagery, NOTAMs and the surface pressure pattern. Compare observations with the forecast. A meaningful difference can reveal that the weather is developing earlier, later or in a different place than expected.
Plan an alternative course of action before departure. Suitable options can include a different level, a route around a weather zone, a nearer destination, a delay or cancellation. Set personal limits and decision points while you have time to think clearly.
A quick pre-flight checklist
Before relying on the charts, confirm:
you have the latest issue;
the validity covers the whole flight;
the F214 boxes and levels cover your route and planned altitude;
every F215 zone and sub-zone crossed by the route has been decoded;
cloud heights have been considered against terrain elevation;
icing, turbulence, thunderstorms, hill fog and freezing level have been assessed;
winds have been used in heading, groundspeed, time and fuel calculations;
current observations support the forecast picture;
an alternative plan is ready if conditions deteriorate.
With a consistent reading order, F214 and F215 become much easier to use. Start with time, move to location, decode the vertical information and finish by asking how the complete picture affects your route. That habit turns a page of abbreviations into a practical plan for a safer flight.
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