It always looks like clouds are so much higher in the sky (altitude) in the summer than in the winter. Is that true? If not, is there some sort of optical illusion? If so, why is that?

I live in Iowa, so I don't know if this is a phenomenon that exists in all climates, just temperate climates, or just the US Midwest. And, for that matter if this actually happens or if I'm just misinterpreting what I'm seeing.

  • $\begingroup$ Really must consider cloud\weather types, it'll vary wildly through different ones. Given that, if we're focusing on towering cumulus (and perhaps stratus?), while I don't know any datasets to prove it, your thinking matches what I'd think reasonable. One suggestion would be that forcing (fronts, storm systems, etc) is stronger in the cooler seasons, so storms can and do form under weaker CAPE (so generally less T\Td difference, lower LCL). I'd also say T increases more\quicker than Td into the warm season too, so higher bases. But real interested to see if someone has a more complete answer. $\endgroup$ Jul 14, 2016 at 7:42
  • $\begingroup$ I would think you'd see that effect just from having a higher dew point and maybe also stronger thermals (due to higher insolation). A nice addition to this question would be how big the difference is - if it's only a few percent, then it's probably not really detectable by human eyes.. $\endgroup$
    – naught101
    Jul 20, 2016 at 1:37
  • $\begingroup$ See also my answer to this question which is applicable. $\endgroup$
    – Tom Newton
    Oct 10, 2017 at 11:17

1 Answer 1


Cloud base varies as response to several factors, normally, cloud bases are lower in the wintertime than during the summer, particularly for stratus clouds.

Cloud development is mostly dependent on temperature and the amount of water vapor in the air. The temperature has to be low enough to cause the air to become saturated. If the air is relatively dry, a colder temperature is required for water vapor to condense into water droplets. During winter, the temperature of the air in the lower part of the atmosphere is lower than during the summer, so stratus clouds can usually form at somewhat lower heights during the winter than during the summer.

This is a generalization that does not hold true under all conditions and at all times.

Also some more regional patterns can be present since the differentiation between Summer and Winter can be difficult to establish, for example in the tropics.

Taken from: https://stab-iitb.org/newton-mirror/askasci/wea00/wea00274.htm

  • 2
    $\begingroup$ Hi Marlon, could you please quote or paraphrase the relevant parts of that page here? Answers like this become really annoying when links go down. $\endgroup$
    – naught101
    Jul 20, 2016 at 1:32
  • $\begingroup$ agree with naught101. if you can copy the relevant bits from the linked page, i'll mark as accepted :) $\endgroup$
    – viggity
    Jul 20, 2016 at 14:33
  • $\begingroup$ I've never been very comfortable with this answer, at least in its explanation... or at the least it is very incomplete. Low-level temperatures are often colder during the winter, but moisture also tends to be lower. Cloud heights for surface based parcels is based on how saturated it is (e.g. its RH) (and whether it gets lifted enough to form the cloud). Both summer and winter have times with near 100% surface RH. $\endgroup$ Dec 17, 2022 at 7:58
  • $\begingroup$ My suggestion is that in the winter the midlatitude locations wind up more often in the cold sector indeed... and then get top-down moistening from approaching warm fronts with lows, and also bottom-up moistening from warm water bodies. So both favor moisture driving temperature changes, and so a more continual Td=T as it moves in, and so longer times and also greater depths of air saturated at low levels. $\endgroup$ Dec 17, 2022 at 8:05
  • $\begingroup$ Playing around with mesonet.agron.iastate.edu/plotting/auto/… generally seems to show that summer sees very low cloud bases as well.. but for shorter time periods, probably indicating thinner clouds, or at least vertical cumulus rather than shallow stratus. But I don't have enough concrete evidence to make a full answer. All I know is that this given answer just doesn't seem to satisfy, so take it with a grain of salt perhaps. $\endgroup$ Dec 17, 2022 at 8:07

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