My informant is my aunt from rural Kerry. I have heard this phrase multiple times as “Red sky at night, sailor’s delight” since I’ve come to America, but I have never heard it in this form in Ireland. She often uses it as a mode of folk-forecasting whether or not the day following a red sky will be fine or not, and she believes that it is accurate more often than not. She learned this from her grandmother, who believed that it was more accurate than the national weather service. She is signified in this conversation by the initials J.O.
J.O.: You’d say this phrase when the sky is particularly red at sunset, not just a bit of pink in it but absolutely red. And that’s normally in the summer, just when the sun is setting. You don’t normally get a red sky in the winter. And it’s a kind of prediction for the nest day’s weather, that it will be a day that would be perfect for a shepherd – that is, bright and sunny, and clear all day. But there’s a second half to the phrase also – “Red sky in the morning, shepherd’s warning.” That is, if you see a red sky in the morning it suggests that the day is going to be cloudy and heavy, and unsuitable for the shepherds to come out with their sheep. There would usually be rain, too, which is no good for the ground under the sheep.
A: I’ve heard the saying since I’ve been in America as “Red sky at night, sailors’ delight. Red sky in the morning, sailors take warning.” Have you ever heard of this?
J.O.: I’ve never heard it like that in my life. I think that must be a regionalism. Ireland is more of a farming country, whereas maybe there’s more of a focus on sailing in America? Or maybe the phrase made its way to Ireland and we just changed it into something more relevant to us?
A: I think that sounds about right. Do you think it works, as a way of forecasting?
J.O.: Oh absolutely. There must be some science behind it though, as people wouldn’t keep saying it if it didn’t work to some extent. Whenever the sky is red enough to be noticeable and trigger that phrase, it must mean that it does work most of the time.
I think that my informant is absolutely right to suggest that this saying is an oikotype of a different yet similar saying involving sailors, or vice versa. As Ireland does not have a particular maritime focus, and is instead rather more focused on pastoral farming, it would make sense to change the subject of the phrase. It would be interesting to trace from which direction this phrase came, if one is to believe in monogenesis – for example did the sailor’s version make its way to Ireland where it was changed, or the shepherds one to America, which is the only place I have heard this version. What is equally interesting is the question of whether or not it works as a method of forecasting. Obviously, it has not been sanctioned as a concrete form of meteorology, and instead is a kind of folk-forecast. But, I agree that a lot of the times it does work, far more often than not to be pure chance. Therefore, perhaps there is some phenomenon with the way the light appears late in the evenings and early in the mornings which would lend merit to this phrase as a way of forecasting, such as the direction from which clear light comes which would suggest a fine day on its way, or an overcast one.