The wind that blows most regularly over an area is called the prevailing wind or prevailing air mass. Winds are named after the direction from which they blow. For instance, if a wind blows from the south-west towards the north-east, it is said to be a south-westerly wind.
The direction from which prevailing winds blow can have a massive influence on the climate of the area over which they are blowing.
Ireland experiences a range of air masses with different sources and tracks, giving us our variable weather (figure 5). Our dominant (prevailing) winds are from the south-west.
Northerly winds (Polar winds): These winds come from the colder, higher latitude areas (further from the equator). They are dry because they absorb moisture as they move downwards into lower warmer latitudes.
South-westerly winds: Ireland’s prevailing wind blows from across the Atlantic Ocean. Heated in winter by the NAC, these winds bring temperate conditions with cool summers and mild winters. They also bring rain because they absorb water while travelling over the ocean before reaching Ireland.
Easterly winds (coming from eastern Europe): These winds are warm in summer and very cold in winter as they are travelling across large areas of land. They are dry because they absorb little water while travelling over land.
Southerly winds (tropical winds): These are warm winds because they come from warmer, lower latitude areas (closer to the equator). They may bring rain if they give off moisture as they approach cooler, higher latitudes.
5. The air masses that affect Ireland’s climate
1. Using examples of specific Irish regions, explain how distance from seas and oceans can affect climate.
2. What is latitude? Explain how latitude can affect climate. 3. Name and describe the four winds that affect Ireland’s climate.
