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Knowing what to do when presented with poor weather conditions is vital for a pilot. So it’s important to understand the differences between AIRMET vs. SIGMET.

As a pilot, you need always to know the weather forecast whenever you’re planning a flight. Flying blind without knowing the weather is never a good idea, and paying attention to when an AIRMET or a SIGMET is issued is essential. But what do these words mean, and what are the differences between the two?

AIRMET and SIGMET weather advisories are issued to warn pilots of potentially hazardous weather conditions in an area they might be flying. AIRMETs are less severe and consist of turbulence, visibility, and icing. SIGMETs are more severe, including thunderstorms, volcanic ash, dust storms, etc.

AIRMET vs. SIGMET weather conditions can be confusing for some pilots. This article will discuss the differences between these two types of weather conditions and why they are important. We'll start with a general overview of AIRMETs and SIGMETs. Then we'll dive into the specifics of each type of weather condition. Finally, we'll talk about when pilots learn about these conditions and how they should handle them in flight.

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Before we get into the differences between the two, let's start off by just talking in general about why AIRMET and SIGMET weather conditions are important to know as a pilot. After all, it's vital that you always check the weather forecast yourself and also check for the issuance of either AIRMET or SIGMET conditions.

AIRMETs are issued for aviation weather conditions that are considered to be potentially hazardous to all aircraft. These conditions include but are not limited to, icing, turbulence, and low visibility. We'll get into much more detail about these shortly, but this is just a quick taste of AIRMETs.

SIGMETs are issued for aviation weather conditions that could pose a danger to air traffic. These conditions include severe thunderstorms, tornadoes, and volcanic ash clouds. Again, we'll get into more detail about each of these shortly.

Now that we have a general idea of what AIRMET vs SIGMET weather conditions are, let's dive into the specifics of each type of condition.

What Are AIRMET Weather Conditions?

AIRMET is short for "airmen's meteorological information." These are weather advisories that are issued for potential hazards to aircraft that are below 18,000 feet. As we mentioned before, these hazards include icing, turbulence, and low visibility. In general, AIRMETs are usually more important for pilots of smaller aircraft since these conditions will most adversely affect those aircraft. But commercial pilots and pilots of other large aircraft must also take these seriously as well.

In order for an AIRMET to be issued, the weather conditions must be widespread enough to merit the advisory. In most cases, this means that it must cover an area of at least 3,000 square miles before it is issued. So if an AIRMET is issued in your area or where you're flying, do not think that it is just the local conditions. It is issued for widespread weather conditions that must be accounted for by every pilot in the area.

These weather conditions are issued by the Aviation Weather Center (AWC) and are typically valid for a six-hour period. That said, the AWC can extend the duration of an AIRMET as it sees fit as well as recall it for change and amendment if necessary. In severe cases, an AIRMET can be withdrawn and replaced by a SIGMET if the conditions worsen and that level of warning is necessary.

What Are The Different Types of AIRMETs?

There are three different types of AIRMETs: Tango, Sierra, and Zulu. Each one means something a little different based on the weather conditions, and knowing what the types refer to make it easier for the pilot to know how to react and make any changes to the flight plan as necessary.

AIRMET T (Tango)

AIRMET Tangos are issued because of turbulence. If an AIRMET Tango is issued, that's because there are either weather conditions present in the area that will contribute to turbulence, sustained winds that could cause turbulence, or turbulence has been reported by other pilots. It's important that pilots pay attention to this because turbulence can be extremely dangerous, especially if you're not flying in a large aircraft that can handle it better.

In the event of an AIRMET Tango, it's important to keep an eye on the weather conditions and avoid any areas where turbulence is likely. If you can't avoid the area, then make sure that you're flying at a higher altitude so that you can better deal with the turbulence.

AIRMET S (Sierra)

AIRMET Sierras are issued to let pilots know that they should only fly under Instrument Flight Rules (IFR) because of the low visibility in the area. This means that there is either a forecast or actual conditions of less than three miles of visibility in at least half of the aforementioned 3,000 square miles affected area. It is also issued if ceilings are at 1,000 feet MSL or lower.

In the event of an AIRMET Sierra, it's important that pilots only fly under IFR conditions. This means that they must be able to fly the aircraft solely by reference to their instruments and not by visual references outside of the aircraft. If you're not comfortable flying under these conditions, then it's best to avoid the area entirely.


AIRMET Zulus are issued because temperatures in the affected area are conducive of freezing and/or icing on the aircraft. This could be due to either actual or forecasted temperatures at or below freezing (0 degrees Celsius or 32 degrees Fahrenheit) at the surface and/or in the clouds. It could also be due to actual or forecasted visible moisture in the form of rain, snow, sleet, or ice pellets.

In the event of an AIRMET Zulu, it's important that pilots be aware of the potential for icing on their aircraft. This could cause serious problems with the aircraft and make it difficult to fly. If you're flying in an area that is affected by an AIRMET Zulu, it's important to keep an eye on the weather conditions and be prepared to turn back or land if necessary. This is also why airplane de-icing is so important and should be fully understood by all prospective pilots.

How Should Pilots Handle an AIRMET?

If you're a pilot and you find yourself in the middle of an AIRMET, the first thing you should do is assess the situation. Take a look at the weather conditions and see if there's anything that you can do to avoid the worst of it. If not, then make sure that you're prepared for whatever comes your way.

If you're flying in an aircraft that is affected by an AIRMET, it's important to be aware of the potential dangers and take whatever precautions are necessary. This could mean anything from changing your flight plan to avoid turbulence to landing at the nearest airport if conditions are too severe.

In any case, it's always better to err on the side of caution when it comes to flying in potentially dangerous weather conditions. If you're not comfortable with the conditions, then it's best to avoid the area entirely.

What Are SIGMET Weather Conditions?

SIGMETs are similar to AIRMETs in that they're both issued to let pilots know about potentially dangerous weather conditions. However, SIGMETs are generally issued for more serious weather conditions than AIRMETs.

SIGMET stands for "significant meteorological information" and they're also issued by the Aviation Weather Center (AWC) to warn pilots of severe or hazardous weather conditions. This could include anything from thunderstorms and tornadoes to volcanic eruptions and ash clouds.

What Are The Different Types of SIGMETs?

The two types of SIGMETs are convective and non-convective. That's a little different than AIRMETs in how they're referred to, but in many cases letters are still used in a similar fashion. You might see SIGMETs noted using letters N through Y, except for any of the letters used to denote AIRMETs to avoid confusion.

Convective SIGMETs

Convective SIGMETs are issued for thunderstorms, tornadoes, and other severe weather conditions that are developing or expected to develop in the near future. These types of SIGMETs are usually issued for a relatively small area and for a short period of time.

If a convective SIGMET is issued for your area, it is important to pay attention to the details of the SIGMET. The most important information in a convective SIGMET is the location, intensity, and size of the thunderstorms. Other important information includes the expected direction of movement of the thunderstorms and any special weather conditions that may be associated with them (heavy rain, large hail, strong winds, etc.).

As a pilot, it is important to avoid flying into convective SIGMETs if at all possible. If you must fly through a convective SIGMET, it is important to be aware of the intensity of the thunderstorms and to avoid flying through areas of severe weather. It is also important to be aware of the possibility of turbulence and to be prepared for it.

Non-Convective SIGMETs (Volcanic Ash, Sand Storms, Dust, etc.)

Non-convective SIGMETs are issued for weather conditions that are not associated with thunderstorms or other more standard conditions. These types of SIGMETs can be issued for a variety of conditions, including volcanic ash clouds, sand storms, dust storms, and severe icing.

As with convective SIGMETs, it is important to pay attention to the details of a non-convective SIGMET. The specific conditions that are being reported will dictate what kind of action, if any, needs to be taken. For example, a volcanic ash cloud may not pose an immediate danger to an aircraft, but it can cause long-term damage to the engines so it is important to avoid flying through one if at all possible.

How Should Pilots Handle a SIGMET?

Any time that a SIGMET is issued, it is important for pilots to be aware of the conditions that are present and how to handle them. The first step is always to avoid the area entirely if possible. If not, then it is important to fly at a higher altitude than normal in order to stay above the clouds. It is also important to keep an eye on the weather conditions and be prepared for changes.

If the conditions worsen, it is important to be able to land quickly and safely. Pilots should also avoid flying through areas with thunderstorms or other severe weather. Flying in these conditions can be very dangerous and should be avoided if at all possible.

When Do Pilots Learn About AIRMETs and SIGMETs?

Pilots learn about AIRMETs and SIGMETs in their weather training. This is important because AIRMETs and SIGMETs are two different types of weather conditions that a pilot needs to be aware of. AIRMETs are issued for less severe weather conditions, while SIGMETs are issued for more severe weather conditions.

In conclusion, pilots need to be aware of AIRMETs and SIGMETs. This will help to keep pilots and passengers safe when flying in less than ideal weather conditions.