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Explore climate patterns, zones and long-term environmental conditions.
Climate · Comparisons
Both storms rotate, both can cause destructive winds, and both appear in dramatic weather images. Those similarities hide an important distinction: a hurricane is a whole weather system,…
Climate · Explainers
A mountain summit is often colder than the lowlands, but “higher means colder” has exceptions. To understand the pattern, separate two questions: what happens to air as it…
Climate · Explainers
“River in the sky” is a memorable phrase, but it can suggest the wrong picture: a suspended stream of liquid water. The real feature is moving moisture, and…
Climate · Comparisons
A winter forecast can change from snow to sleet to freezing rain even while your outdoor thermometer stays below freezing. The missing information is above your head: falling…
Climate · Explainers
Changing the baseline shifts the anomaly numbers for an unchanged annual temperature series, sometimes reversing their signs, while preserving every year-to-year temperature difference. With one fixed reference mean…
Climate · Explainers
To read a weather station model, check the time, units and legend, then decode the numbers around the station circle and the wind shaft attached to it. In…
Climate · Explainers
To read a wind rose, match each spoke to the direction the wind came from, read its length against the frequency rings, and use the colors to identify…
Climate · Explainers
To read a climograph, identify the months, temperature line, precipitation bars and their separate labeled axes. Read each value on its own scale, then compare the seasonal pattern.…
Climate · Explainers
For horizontal motion, the Coriolis contribution acts to the right of travel in the Northern Hemisphere and to the left in the Southern Hemisphere. Right and left follow…
Climate · Comparisons
Relative humidity is the percentage ratio of actual water vapor pressure to saturation vapor pressure at the air temperature. Dew point is the temperature at which cooling would…
Cities & capitals · Explainers
An urban heat island is an urban area that is warmer than its surrounding reference area. Built surfaces, reduced vegetation, building geometry and human-generated heat can all contribute.…
Climate · Map guides
A weather front is a transition zone between air masses with contrasting properties, especially temperature. Cold and warm fronts describe one air mass replacing another at the surface.…