Using Clouds to Predict the Weather

We surface observers admire clouds for their beauty, but clouds are more than just pretty puffs. In fact, clouds can help you predict upcoming weather. Look out for these eight cloud types next time you're out backpacking or boating to avoid being caught off guard by a "sudden" rainfall or thunderstorm. 

01
of 08

Cumulus Clouds: All Is Fair

Clouds MGM-440.JPG
Tiffany Means

Isolated cirrus occur in fair weather. Because they point in the direction of air movement, you can always tell what direction the wind is blowing at upper levels by simply observing the direction in which the cloud wisps are oriented.

However, if a large number of cirrus are overhead, this can be a sign of an approaching frontal system or upper air disturbance (such as a tropical cyclone). Therefore, if you see a cirrus-filled sky, it's a good indication that weather conditions may soon deteriorate.

Precipitation Cloud: No

02
of 08

Cirrus Clouds: All Is Fair (For Now)

cirrus-sky
Wispy cirrus clouds. Westend61/Getty Images

Isolated cirrus occur in fair weather. Because they point in the direction of air movement, you can always tell what direction the wind is blowing at upper levels by simply observing the direction in which the cloud wisps are oriented.

However, if a large number of cirrus are overhead, this can be a sign of an approaching frontal system or upper air disturbance (such as a tropical cyclone). Therefore, if you see a cirrus-filled sky, it's a good indication that weather conditions may soon deteriorate.

Most Likely Weather: The weather is fair, but a change will occur in 24 hours

Precipitation Cloud: No

03
of 08

Altocumulus Clouds: Warm With a Risk of Storms

altocumulus-sky
No Photo, No Life!/Getty Images

Altocumulus are popularly called "mackerel sky"—and for good reason. Besides resembling fish scales, the clouds (which are commonly seen on warm spring and summer mornings) can signal the development of thunderstorms later in the day.

Altocumulus are also commonly found between the warm and cold fronts of a low-pressure system, and sometimes signal the onset of cooler temperatures.

Precipitation Cloud: No (but signals convection and instability at mid-levels of the troposphere)

04
of 08

Cirrostratus Clouds: Moisture Moving in

cirrostratus-sky
Cultura RM/Janeycakes Photos/Getty Images

Cirrostratus indicate a large amount of moisture in the upper atmosphere. They're also generally associated with approaching warm fronts. (Watch for cloud cover to thicken the closer the front nears.)

Precipitation Cloud: No (but may signal impending precipitation in the next 12-24 hours, or sooner if the front is fast-moving)

05
of 08

Altostratus Clouds:

altostratus-sky
Hiroshi Watanabe/Taxi Japan/Getty Images

Altostratus tend to form ahead of a warm or occluded front. It can also occur together with cumulus at a cold front.

Precipitation Cloud: Yes (can produce light rain and virga)

06
of 08

Stratus Clouds: Fog

stratus-sky
Matthew Levine/Moment Open/Getty Images

See stratus hanging overhead? Expect drizzle or snow flurries. Other than that, they don't indicate much meteorological activity.

Precipitation Cloud: Yes, light

07
of 08

Cumulonimbus Clouds: Severe Storms

cumulonimbus-sky1
Peter Zelei/E+/Getty Images

Just like you see a cumulus cloud and know it means fair weather, cumulonimbus mean the weather is stormy. (Ironically, it is the very act of these harmless fair weather cumulus clouds overdeveloping that creates cumulonimbus.) Any time you see a cumulonimbus on the horizon, you can be sure that dangerous severe weather—such as short periods of heavy rain, lightning, hail, and possibly tornadoes—isn't far off.  

Precipitation Cloud: Yes (often intense rain)

08
of 08

Nimbostratus Clouds: Rain, Rain Go Away!

nimbostratus-sky
James O'Neil/Stone/Getty Images

Nimbostratus is a sign of steady moderate to heavy rains and can last for several days on end.

Isolated cirrus ​can occur in fair weather. Because they point in the direction of air movement, you can always tell what direction the wind is blowing at upper levels by simply observing the direction in which the cloud wisps are oriented.

However, if a large number of cirrus are overhead, this can be a sign of an approaching frontal system or upper air disturbance (such as a tropical cyclone). Therefore, if you see a cirrus-filled sky, it's a good indication that weather conditions may soon deteriorate.

Precipitation Cloud: Yes