For the total solar eclipse on April 8many people will strive to be within the path of totality, where the sun’s face is completely blocked by the moon’s shadow. But even if you are within this path, it does not guarantee that you will have clear skies on the day of the eclipse.
So what happens if it’s cloudy where you are on April 8? Will you notice anything when the shadow of the moon sweeps over you?
That depends on how thick and how extensive the clouds are. Either way, you’ll definitely notice it very unusual effects when the shadow of the moon passes. I’ve been unlucky enough to be completely clouded by two of the thirteen in total solar eclipses I traveled there, and in a third case I managed to sneak a view of the corona, even though almost the entire sky was cloudy.
Related: How to give yourself the best chance of clear skies during the April 8 solar eclipse
So, based on these three experiences, here’s what to expect when the weather doesn’t work in your favor and you end up having to say those two words every eclipse chaser doesn’t want to hear: “Cloudy!”
If you can’t see the eclipse in person or the weather is unfavorable, you can watch the total solar eclipse live here on Space.com. And stay up to date on all the action with our total solar eclipse 2024 live updates blog.
Passage of the shadow of the moon
Should there be significant cloud cover on “E-Day”, the clouds may even have an advantage: they will provide a projection screen of sorts to view the rapid approach and departure of the moon’s dark shadow. Isabel Martin Lewis described the effect in her 1924 book ‘A Handbook of Solar Eclipses’.
“At the time of the solar eclipse, when the moon’s shadow sweeps over us, we are brought into direct contact with a tangible presence from the space beyond and feel the immensity of forces beyond our control,” Lewis wrote. “The effect is utterly awe-inspiring. In fact, the passing of the moon’s shadow, if you are lucky enough to observe it, will be one of the most impressive features of the eclipse.”
Medium to high clouds
If your sky is covered with medium to high clouds – cirrostratus, altostratus and/or cirrocumulus – you will likely be able to see the leading edge of the elliptical shadow moving quickly toward you and then over you just before and at the onset of totality . And with its passage there can be a remarkable change in the overall quality of light on the surrounding landscape and a dramatic change in the color of the clouds.
On July 10, 1972 at my very first total solar eclipse, my family and I were just outside Cap-Chat, Quebec, a sleepy Canadian community of 2,000 whose population swelled to almost 30,000 on the day of the eclipse. The eclipse started under a bright sun mixed with some wispy high clouds. But as more and more of the sun became covered, the high clouds rapidly increased and began to decrease, so that at the onset of totality almost the entire sky was covered by a band of gray battleship clouds.
But when the moon’s shadow arrived, we saw its distinctly sharp edge moving inward. For those of a certain age who may remember the long-running television soap opera ‘The Edge of Night’, the opening of which featured an animation of a line of darkness blowing over a city, that’s exactly what I was thinking of as we were enveloped by the shadow of the moon. Once you experience it for yourself, it becomes easy to understand why this sight was so terrifying to ancient people.
Along with the sudden darkness came a change in the color of the clouds. Behind the forward-moving edge of the moon’s shadow were strange and exotic colors. The dull gray suddenly became yellow-orange and shades that you would see if you looked through a beer or iodine bottle. In fact, along the edge of disappearance Sun at the beginning and end of totality, an arc of ruby red or fuchsia appeared associated with the solar chromosphere. It looked bright red because the hydrogen in the sun emitted a reddish light at high temperatures, and some of this light can become visible in the clouds at the beginning and end of totality.
Some final comments on my eclipse experience in 1972. Despite heavy cloud cover, we managed to see the totally eclipsed Sun through a chance opening in the cloudy sky about 30 seconds after totality began. As totality came to an end, we clearly saw the trailing edge of the shadow, projected on the clouds, rushing away to the northeast. I remember my grandfather shouting to my grandmother, “Inez! Look, look! It’s going that way.’ Meanwhile, my sister Lisa, who was taking it all in, simply said, “That’s it foreign!“
“Incredible sight!”
Interestingly, in March 1970, during special coverage of the total solar eclipse on CBS TV, correspondent Bill Plante (1938-2022) was stationed in Halifax, Nova Scotia under cloudy skies. Yet he was very alert to the changes that took place as the moon’s shadow moved in.
“In the last 30 seconds we have witnessed the most incredible sight – despite the fact that we cannot see the sun – as it has become as dark as night!” he said. “The light has dropped so quickly, from an acceptable twilight or reading level or cloud cover level, to a virtual night. And just to the north and east, beneath this layer of dark, dark sky, is a beautiful pink and orange horizon; a orange and gold color. We say again: it was just an incredible and fascinating phenomenon to have the sky darken so suddenly, in less than 30 seconds, and now we have this totality of a solar eclipse!’
It sounds like Plante was impressed, despite the clouds.
Just a few clouds
Sometimes you are lucky enough to get mostly clear skies. But even then, unfortunately, one of the few clouds in the sky may be in front of the sun during the total phase of the eclipse.
That happened to me on October 12, 1977 in Colombia, South America. During the 38-second interval of totality, a single cloud drifted in front of the sun. If something like this happens to you, your best bet is to look around the dark sky for some of the brighter stars and planets and try to watch for the passing of the moon’s shadow.
As I later noted in my personal diary: “When totality arrived, virtually the entire sky was clear and visibility and transparency were almost excellent. We could easily see seven stars and on third contact were impressed by the passage of The moon’s shadow cone quickly retreated to the east, and in the east part of a rainbow turned completely red as totality began.
There was only one thing wrong: the sun was behind a cloud! It began entering the Sun a few minutes before totality and left only a minute or two after the Sun began to reappear. As if to rub salt in the wound, not another cloud intervened, even as the partially eclipsed sun set behind the Andes! For me, Colombia was Cap Chat in reverse. What goes around, comes around!”
For more information on this setback, read my colleague Comments by Glenn Schneider.
Thick, low clouds
Finally, on the day of the eclipse, your view may be obscured by clouds at low altitudes, usually below 6,000 feet. They are usually thick, low, flat clouds that cover large areas and often bring precipitation.
In December 2021, my wife Renate and I were aboard an icebreaker, sailing off the coast of Antarctica, when we encountered the moon’s shadow for a total solar eclipse that lasted just over a minute and a half. Unfortunately, our skies were overcast with low clouds and spotty, light precipitation.
In such a situation, the effects of a total solar eclipse can best be described as being in a lit room where someone turns a dimmer switch down and then up again, causing the light to return.
As I noted in my story for Space.com“Totality lasted 97 seconds. No clear shadow or cone of darkness was noted. Rather, just an amorphous darkening of the sky – as if someone turned down a rheostat or dimmer switch. No colors were seen and the end of totality seemed more pronounced when the light seemed to return faster than when it disappeared. During the whole it even started to drizzle very lightly and a few minutes after the third contact it even started to snow lightly. The air temperature hovered around 0°C (32° C). F), but if you take the wind into account, it feels noticeably colder.”
Final thoughts
I suppose Antarctica was the most disappointing of all my eclipse experiences; Besides the fact that it became dark and light again, there wasn’t much to see anymore. I hope that anyone who positions themselves in the path of the moon’s dark shadow will get a clear view of the April 8 solar eclipse. But as you can see, unless the clouds are low and thick and there is some rain or snow falling, the moon’s shadow passing by and the eerie colors that come with it should still make for quite a spectacle!