High pressure
Also called high, anticyclone, H on a map
Weather-map symbol. A chart convention, not a forecast icon.
Weather-map symbolsHigh pressure meaning
High pressure on a weather map is the letter H at a pressure center. NESDIS teaches it in blue. The letter still has to be readable without the blue.
At a glance
- System
- Synoptic chart convention
- Used for
- A high-pressure center
- Not the same as
- A clear-sky icon, or a ridge
An H for a high-pressure center. The letter is the symbol. Color is extra.
The name. The letter H is the mark. Blue is a common aid. Fair weather is usual, not a guarantee written into the letter.
Where it comes from
NESDIS, in its guide to reading a weather map, marks a high with a blue H and says highs usually bring fairer, drier weather. The National Hurricane Center glossary also names a blue H. “Usually” is the teaching word. A high is a center of higher pressure relative to its surroundings, not a promise of a clear-sky icon. Isobars around it are the pressure field. The H is the label of the center.
The line drawing is original to this cabinet. It is not an agency logo, a vendor icon, or the emoji for the same idea.
Weather
What it means
Air is heavier there than nearby, in the analyst’s pressure field. Winds around a high are a circulation, plotted with barbs if the map shows stations. The H does not point the wind. It names the center. A ridge is an elongated extension of higher pressure, not this letter.
Questions
What does H mean on a weather map?
A high-pressure center. NESDIS draws it blue and describes highs as usually fairer and drier. The letter is the mark. Blue is the aid.
Does H mean the forecast is sunny?
Not as a symbol. Sunny is a forecast icon. H is a pressure center. They often agree and they are not the same sentence.
Near this
- Low pressureAn L for a low-pressure center. Not a rain icon, and not a cold front.
- IsobarA line joining equal pressure. The number is the pressure. The line is not a front.
- RidgeElongated higher pressure. The zigzag is a reading aid, not a WMO code.
- Clear skyA forecast icon for an expected open sky. Not the alchemical sun, and not a clear night.
Sources
- NESDIS, how to read a weather map
- National Hurricane Center, USA glossary
- NOAA JetStream, surface weather maps
Named when the entry depends on a text, a date, or a standard. Catalog numbers are not invented.
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symbol.wiki, edited as Sigilla. Last reviewed 18 October 2026. A reading of public tradition, not a ruling.