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As I look for a spot for viewing the total eclipse, how much will cloud cover affect the viewing experience? Is there a threshold list like:

Under x % won't have a noticeable difference Over x % you won't be able to see the stars Over x % you won't be able to see the sun's atmosphere Over x % you will only notice the darkening

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    $\begingroup$ Even if there is only a single cloud in the sky – if it happens to be right in front of the sun during totality, you won’t see the corona. So, any number except for 0% and 100% isn’t going to tell you much. I was lucky in the 1999 European eclipse, it was rather cloudy but the sun was mostly unobscured during totality. $\endgroup$ – chirlu Aug 19 '17 at 16:20
  • $\begingroup$ Even if it’s cloudy, the darkening is more dramatic than you think. Every time in your life that you have ever seen it getting darker, the daylight has got yellower as well. In a solar eclipse it stays the same colour. It is much more disorientating than you might think. You find yourself in an alien world or a painting by Caspar David Friedrich. $\endgroup$ – Martin Kochanski Jul 1 at 8:42
  • $\begingroup$ High level Cirrostratus, covering the sky, such as we are seeing more as the climate heats up does not do much to distort totality. Corona will be a little dimmer, a little less detailed, but not so as you'd notice with an eye behind a proper filter. $\endgroup$ – Wayfaring Stranger Jul 2 at 2:03
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I don't know if there is a list but I'me sure your local weather surface will give you some idea. Cloud cover could have a big effect of course. But it will be the same as it is for any day or night. Total overcast will allow you to notice the darkness only. Just use your common sense on what cloud cover you deem too risky for travel. There is an internet site: https://clearoutside.com/forecast which is supposedly developed by astronomers to help determine viewing conditions. Just input a latitude and longitude and it gives you info related to viewing conditions. Different days are on left after local forecast. Click the triangle in the lower right of the date and it gives you a detailed forecast for the location you entered. This includes predicted cloud cover by the hour.

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  • $\begingroup$ I have looked at clearoutside.com/forecast but I'm not sure how to interpret the data. I will have to drive 7-8 hours on Monday just to get to a viewing location so I want to know how likely that long drive is to be worthwhile. $\endgroup$ – James A. N. Stauffer Aug 19 '17 at 21:45
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    $\begingroup$ Probably the most pertinent features are the probability of rain and the expected cloud cover. Select the How To text at top of page and it will take you on a guided tour of the display. This helped me a lot. I just had to be sure and tap the pause button whenever it changed to a new section. The pause and other buttons briefly appear on the screen when it changes which part of the page it's describing. The hourly listing of anticipated cloud cover is what I'd focus more on. The less cloud cover the better chance for viewing. Just put lat, long of place you're considering for viewing. $\endgroup$ – jmh Aug 19 '17 at 21:57
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Well,I don't mean to answer a question with a question, but: on a cloudy day, can you see the sun through the clouds?

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  • $\begingroup$ During an annular eclipse, I used a thin overcast as a solar filter for taking pictures. Didn't try looking at the sun, but it did bring the light level down far enough for my camera to handle. $\endgroup$ – Mark May 5 '18 at 2:06
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In preparation for the Aug 1999 total solar eclipse, I travelled to a friend's house in Honiton, Devon (south coast UK), the day before the eclipse. We were deciding the best place to visit to view the eclipse. That evening I checked the satellite imagery on the internet and saw that clouds were coming in from the west and so the best chance would be to go as far east as possible while remaining in the path of totality. So I checked the online map and Torbay seemed a good place. Luckily, we were travelling almost due south and this worked out very well because the roads were clear - everyone was travelling east to Cornwall. Although it was cloudy, there were frequent gaps and we got some great clear views of Baily's beads including the corona during totality. In Cornwall, they saw nothing - it was a complete white-out for the entire eclipse. I was one of the very few who actually got to see it in the UK. Ok, we were lucky in some regards, but performing the cloud/wind direction checks was essential in our case.

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  • $\begingroup$ I’m not sure if this is really an answer... $\endgroup$ – Max0815 Oct 29 at 14:23

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