Portsmouth Pressure & Humidity
Calderdale — Barometric Trends
Portsmouth Pressure & Humidity Outlook
Portsmouth starts the day with the barometer around 988 mb, decidedly low overall, with humidity running high, so it can feel a bit close at times. That raises the chance of a more changeable spell at times, even with quieter windows in between. The range looks fairly wide across the outlook, so the support for settled weather may come and go. Later on, the balance can tip a touch more settled at times.
Over the coming days, pressure is likely to sit between 990 mb and 1022 mb in the days ahead. Pressure trends higher through the coming days, favouring quieter spells 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
When forecasts change between updates, it is commonly driven by small shifts in storm track or blocking position. The links below give stable context that helps you read those changes.
- England Climate for regional patterns and seasonal tendencies.
- UK Climate Overview for a national baseline and how regions compare.
- England 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 Portsmouth today?
In Portsmouth today, pressure is around 988 mb. It helps describe the broader set-up, while cloud, fronts and local effects still decide the day-to-day detail. Later in the outlook, pressure trends a little higher, which can bring quieter interludes 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 Portsmouth?
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 Portsmouth?
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 Portsmouth?
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.