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Pressure
Areas of high and low pressure on a weather map are labelled "H" and "L" respectively. If you live in a low-pressure area, expect some rain, which may be shown on the map by a cloud with rain falling from it. If you are in a high-pressure area, you can probably look forward to blue skies and sunshine. The amount of sunshine or rain depends on the amount of pressure. Low-pressure areas can produce anything from a shower to a torrential deluge.
Isobars
Isobars are lines of equal air pressure and they usually have a number on them that indicates the air pressure in millibars. For example at the center of a high-pressure system, the number is higher. When isobar lines are close together, this indicates strong winds that are typical of low pressure. When the lines are wide apart, you can expect the calm, sunny weather associated with high pressure.
Wind Patterns
High and low pressure affect wind direction. In the northern hemisphere, wind flows counterclockwise around areas of low pressure and clockwise around high pressure systems. It is the opposite in the southern hemisphere. Follow the isobars out from the center and you´ll see from which direction the wind is coming. Wind coming from a high latitude is generally cold, while wind coming from low latitudes close to the equator is warm.
Fronts
Fronts are air masses of different temperatures and they are indicated by lines. Lines showing a cold front have triangles on them; lines showing warm fronts have circles. Follow the direction in which the triangles and circles are pointing and you´ll see which way the front is heading. The approach of a front usually indicates a change in the weather. A line with triangles on one side and circles on the other shows a weather front that is not moving.