Greencastle Pressure & Humidity
Belfast — Barometric Trends
Greencastle Pressure & Humidity Outlook
For Greencastle today, pressure is around 1004 mb, slightly on the low side, with humidity sitting in a comfortable middle range. That can keep things a touch more changeable, with cloud and wind shifts shaping how it feels. With a wide spread in values, the background feel can swing between steadier and more mixed spells. A slight fall later on would keep the more changeable edge in play.
Through the period, pressure is projected to run between 988 mb and 1013 mb across the outlook period. Pressure is projected to edge lower through the period, which can encourage a more changeable feel at times. Humidity looks generally high, which can help low cloud to linger in calmer spells.
Current Readings
Pressure
Humidity
Dew Point
Today’s Hourly Humidity
Today’s Hourly Pressure
14-Day Trends
Humidity Chart
Pressure Chart
Forecast context and reference links
Forecast charts summarise likely conditions, but day-to-day outcomes in the UK often depend on how the larger pressure pattern evolves. Use the context links below to interpret the signal more reliably.
- Northern Ireland Climate for regional patterns and seasonal tendencies.
- UK Climate Overview for a national baseline and how regions compare.
- Northern Ireland for location browsing and regional navigation.
How to interpret confidence
For how forecast reliability changes with lead time, see Forecast Confidence. For transparency on how WeatherEngland sources and updates data, see Methodology.
Background guides
- UK Weather Patterns
- UK Seasonal Weather
- UK Weather Hazards
- UK Weather Safety
- UK Jet Stream
- UK Microclimates
Glossary support
Start with the Weather Glossary. Useful terms for this page include Isobar, Pressure Gradient, Relative Humidity, Dew Point, Anticyclone, and Depression.
FAQ
What is the air pressure in Greencastle today?
The barometer in Greencastle is sitting near 1004 mb at the moment. It gives a sense of the overall pattern, though the local detail still comes down to cloud cover and wind. As the period goes on, the barometer trends down slightly, which can support a more variable, Atlantic-leaning set-up at times.
What counts as high or low pressure in the UK?
In UK terms, pressure in the low 1020s (around 1020 mb–1024 mb) often supports a steadier background, while the low 1000s (around 1000 mb–1004 mb) more often sits closer to passing low-pressure systems. What matters most is the wider pattern and whether pressure is rising or falling.
How does pressure affect wind in Greencastle?
Pressure influences wind through the regional gradient. When the pattern tightens, winds can pick up; when it relaxes, winds usually ease.
Does low pressure always mean rain in Greencastle?
Not necessarily. Low pressure favours rising motion and cloud development, but rainfall depends on available moisture, frontal features and the track of the system. Some low-pressure days are simply cloudy and breezy with only patchy showers.
What does humidity mean for comfort in Greencastle?
It is the amount of water vapour in the air relative to its capacity at that temperature. When humidity is high, evaporation slows and the air can feel damp; when it is lower, comfort and visibility often improve. Moisture levels stay on the higher side overall, so visibility can drop more easily in calmer spells, with low cloud more prone to linger.