What Is Mostly Clear?
Mostly clear is a sky condition where the majority of the sky is free of clouds, but a small amount of cloud cover is still present.
During the day, mostly clear conditions generally allow plenty of direct sunshine. At night, most stars and other objects in the night sky remain visible, although occasional clouds may pass overhead.
Mostly clear conditions are often associated with settled weather, but they can occur during both warm and cold weather. The term describes the amount of cloud cover rather than temperature, wind or precipitation.
Related Conditions
| Condition | Description |
|---|---|
| Clear Skies | A sky condition with little or no cloud cover. |
| Partly Cloudy | A mixture of clouds and clear sky, with more cloud cover than mostly clear conditions. |
| Mostly Cloudy | A sky condition where clouds cover most of the sky while some clear areas remain visible. |
| High Thin Clouds | Thin clouds high in the atmosphere that may be present while much of the sky still appears clear. |
| Fair Weather | Generally settled weather with limited cloud cover and little or no precipitation. |
Related Alerts
| Alert | Description |
|---|---|
| Frost Advisory | Issued when temperatures near the ground are expected to become cold enough for frost to develop during the growing season. |
| Extreme Cold Warning | Warns when very low temperatures or wind chill create dangerous cold conditions. |
| Heat Warning | Warns when temperatures or humidex values are expected to create potentially dangerous heat conditions. |
| Air Quality Warning | Warns when poor air quality is expected to pose an increased health risk. |
| Wind Warning | Warns when strong winds are expected to create hazardous conditions. |
What Causes Mostly Clear Skies?
Mostly clear skies develop when atmospheric conditions limit widespread cloud formation but still allow a small number of clouds to develop or move through the area.
High pressure frequently contributes to this weather condition. Sinking air associated with high-pressure systems tends to warm and become less favourable for condensation, making widespread cloud development less likely.
Dry air can have a similar effect. When there is relatively little moisture available in the atmosphere, only isolated or thin clouds may be able to form.
Mostly clear conditions can also occur as a weather system moves away. Existing clouds may gradually break apart, leaving increasingly large areas of open sky. If the remaining clouds continue to dissipate, conditions may eventually become clear skies.
At night, limited cloud cover allows the ground to lose heat more efficiently. Clear and calm conditions can therefore contribute to substantial overnight cooling and, during the growing season, may help create conditions favourable for frost.
FAQ
This means only a small portion of the sky is covered by clouds while the majority remains clear.
Clear skies have little or essentially no cloud cover. Mostly clear skies contain a small but noticeable amount of cloud.
It is possible for rain to occur nearby while most of the sky remains clear, but widespread precipitation is not normally associated with clear conditions.