Seeing the weather is something we do on a daily basis. However, we may not understand well when the weatherman points to the map. We see the map of Spain with many lines, symbols and numbers. What do all those signs refer to?
Here you can learn everything you need to know to read and perfectly understand the weather map . Just keep reading and ask if you have any questions 😊
Basic principles of the weather map
Weather maps offer a simplified representation of current or forecast weather conditions in a given area. It's most common to analyze the surface, since that's where weather affects us. General meteorological concepts are easy to understand. Most people need information about precipitation, winds, storms, hail, snow , and so on.
These aspects are quite important when it comes to understanding the weather: what it takes for it to rain, why it happens, and how intensely. To understand how many meteorological variables work, it's vital to know about atmospheric pressure . Atmospheric pressure, in most cases, determines the weather. In places where atmospheric pressure is higher, good and dry weather predominates. Conversely, if it's lower, there will be more humid air and bad weather. You can also consult our synoptic maps to see the weather information more clearly.
Importance of atmospheric pressure
When there is a higher pressure system, it contains a denser mass of air . This is because the air is cooler and drier than the surrounding air. When this happens, the denser air sinks and moves away from the higher pressure system. This is when we experience clear, sunny weather with few clouds.
On the other hand, when we have a lower pressure system, it means that the air mass is less dense. This is because the air is more humid or hotter. Thus, the surrounding air goes inwards, to the center of the system, while the light air goes upwards. When light, warm air rises and encounters cooler layers, it condenses into clouds. As the clouds grow vertically, the famous precipitation clouds form.
Storms form in systems where pressure is very low. These clouds will form and move across the sky. For these clouds to form, warm, moist air must rise significantly to generate vertical development.
When you look at a weather map, try to analyze how it measures pressure. Pressure measures the weight of the air above the ground. The unit of measurement is the millibar. This is important to understand because many weather patterns are associated with atmospheric pressure. The average pressure at sea level is 1013 mb . When there is a high-pressure system, it usually reaches values ​​of 1030 mb. However, when the system is low-pressure, the values ​​can drop to around 1000 mb or even lower. For a better understanding of weather variations, you can view the interactive weather map.
Symbols on the weather map
To learn the most important symbols on a weather map, pay attention to those related to pressure. To read surface barometric pressure, you look at isobars . These are lines that mark the same atmospheric pressure at different locations. In other words, if you see a map where the isobars are very close together, bad weather is expected. This is because pressure values ​​change rapidly over short distances, indicating atmospheric instability.
Isobars indicate wind speed and direction. Winds blow from areas of higher atmospheric pressure to areas of lower pressure. Therefore, we can determine this information simply by analyzing the isobar values. When isobars are plotted on smaller circles, the center indicates a center of pressure. This can be either high, represented by the symbol A, or low, represented by the symbol B.
We must understand that air does not flow downwards along pressure gradients. It moves around them due to the Coriolis effect (caused by the Earth's rotation). Therefore, isobars that run clockwise represent anticyclonic flows, and counterclockwise isobars represent cyclonic flows. An anticyclone is synonymous with high temperatures and fair weather. A cyclone is an area of ​​atmospheric instability that manifests as a low-pressure system. The closer the isobars are to each other, the stronger the wind speed. If you would like more information on how these phenomena are measured, you can visit our section on real-time weather applications.
Interpretation of a low and high pressure system
When a cyclone occurs, it is usually accompanied by storms with increased cloud cover, winds, temperatures, and precipitation. This is represented on the weather map by closely spaced isobars. The arrows point counterclockwise in the Northern Hemisphere and have a "T" on the middle isobar.
High-pressure systems do not produce rain. The air is drier, and they are represented by an H on the middle isobar. The arrows point in the direction of the wind, clockwise in the Northern Hemisphere. You can also refer to our guide on anticyclones and cyclones to learn more about these phenomena.
Front types
In the meteorological maps that they show us on television, the fronts can be seen indicated. If the fronts pass through an area, it is very likely that the weather will vary. Mountains and large bodies of water can distort your path.
There are several types of fronts, and they are represented on weather maps by different symbols. The first is the cold front. When a cold front passes through an area, torrential rainfall and strong winds are very likely. On weather maps, they are represented by blue lines and triangles on the side indicating the direction of the front's movement.
The second type is a warm front. It involves a rise in temperatures as it approaches. The sky clears quickly as the front passes. If the warm air mass is unstable, some thunderstorms may occur. These are represented on the weather map with red lines and semicircles indicating the direction they are moving.
The last type is an occluded front. It forms when a cold front passes over a warm front. Occluded fronts are associated with weather effects such as thunderstorms. There can be either a warm or a cold occlusion. When an occluded front approaches, the air becomes drier. Occluded fronts are represented by a purple line and semicircles and triangles in the direction of the wind.
I hope that with this information you can learn to interpret the weather map. If you have any questions, leave them in the comments. We will be happy to answer 
