I also notices (yesterday in the device) that icon 3 was listed as partly-cloudy-night and I can not figure out why it was listing the night icon, or, for that matter, why any night icon would show up on the list of daily icons - am I missing something? Or should I wait until it is out of beta testing?
To those of you who notice night icons showing up during daytime hours, this is an intended feature from Dark Sky, but they might change it.
Here is their explanation:
How do you determine the value for the icon property on daily data points?
Our system is presently very simple: it finds the “worst” weather condition that will happen during the day (4AM to 4AM), and uses the icon for it. The only case where a daily icon will show a *-night value is partly-cloudy-night, and this is done to match the daily summary text. We already have intentions to change this behavior, because it is confusing.
In the meantime, you can assume that if partly-cloudy-night is the worst weather condition that was found, that it was clear during the day. So you can just treat partly-cloudy-night as an alias for clear-day.