Instant Weather Forecasting #2 Red Sky In The Morning Means…

Red Sky In The Morning; Sailors Warning

Most people today live blissfully in a totally climate-controlled existence.  We love to chat sociably about the weather with friends and strangers, but alas; we usually have a fairly limited understanding of these patterns, at least in comparison to our ancestors. Thanks to the ubiquitous (and rather welcome, actually) technologically-controlled comfort in our lives, we’ve almost completely lost the hard-earned tribal weather wisdom that had previously been passed from oldsters to youngsters for millennia.

I’m going to assume that most of the “Grow Your Own” gang has increasingly embraced the necessity of getting outside our comfort zones; getting ourselves outdoors, and building for ourselves a more natural, healthy, self-sufficient, enjoyable and sustainable lifestyle.  That lifestyle will inevitably bring some very pleasant and some decidedly unpleasant exposure to the elements.

So where might we find some of this great old weather wisdom?  For most of history, farmers, shepherds and sailors have depended on their ability to ‘read’ the weather.  In this column we’ll be deconstructing the weather proverbs and poetic sayings that those folks have developed to help learn and recognize the classic recurrent patterns of nature.

The first ancient expression we’re going to investigate is “Red sky in morning, sailor take warning, red sky at night, sailor’s delight.”  To understand this one, we need to establish 4 things:

1)     This adage tends to work best in the mid-latitudes, from about 30 degrees north of the equator, to about 60 degrees north.  That happens to be where most of the people live in the US and in Europe, etc., and where most of the ships used to ply the Atlantic waters between the various countries and colonies.

2)     Most of the weather systems in these regions tend to move from west to east. We’ll talk lots more about why this is so in future columns.  As a very, very approximate rule of thumb; we’ll call this speed about 15 mph.

3)     In a nutshell, when the sun is lower in the sky, a clean atmosphere will give you a blue sky, and a dirty atmosphere will tend to be reddish. The red color is an optical effect that comes from sunlight being scattered and refracted (bent) by particulate matter suspended in the air.  For now, just memorize you’ll usually see such “dirty” air in a High pressure area.  That dirty air can be illustrated by the smog over Los Angeles, or the sea salt over the Atlantic.

4)     Weather is generally cloudy, rainy, stormy, windy, etc. in Low pressure areas (bad for sailors), and generally dry and clear in High pressure areas (good for sailors). Here’s a good website to keep handy as we talk about the big picture weather map:

http://www.weather.com/maps/maptype/currentweatherusnational/uscurrentweather_large.html   Note on the map how Lows (“sailor take warning”) are depicted by a big red “L” … and High pressure areas (“Sailor’s delight”) of course are indicated by a big blue “H.”


Thus the highs and lows spin like dance partners, from left to right across the continental dance floor if you will. That’s actually not a bad metaphor, as Lows do indeed spin counter-clockwise, and Highs spin clockwise. We’ll explore why that is in later columns.

Now, having introduced all the players, let’s say you’re a sailing captain in the middle of the Altantic 300 years ago. (Or perhaps a tomato gardener in Des Moines today).  If you see a red sky in the morning (of course you are looking east)  it means that the sun’s rays have been refracted to red by lots of dust and salt particulates in your current high pressure air. This often means that the next weather you can anticipate is a Low pressure area coming at you (“sailor take warning”) from your west. If you see the barometer falling (the pressure is lowering) that will be the confirmation that a low is indeed coming and you might want to rig for bad weather.

If you’re that same sailor or gardener, and you see a blood-red sunset, it likely means that you are looking west into a high pressure area that’s probably going to bring you pleasant, stable, non-stormy (“sailor’s delight”) weather for your evening.

This is Capt’n Dave signing off till next week.  I welcome comments, criticism, suggestions and questions of all sorts.  If you’ve heard one of those old timey phrases you would like explained, please put that in the comments box and I’ll get to it.

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This post was written by Marjory


  • Casey says:

    Hi Marjory, How are you today? My name is Casey and I am a retiree living in Mexico. A couple of interesting notes on weather.

    My Grandfather…an old farmer in Ohio told me that you could tell if rain was imminent by watching the sassafras trees. He said they would turn a lighter green immediately before a rain. He said they turned their leaves upside down to take asvantage of the rain to clean their waste disposal system under the leaves.

    I watched for years, and many trees do roll their leaves before rain. Maybe it is just due to the wind. But it always used to alert me to rain. BTW, Grandpa also had an old-fashioned pitcher barometer on the wall. One day the pressure dropped so steeply that the barometer dumped it’s blue-tinted liquid down the wall. Grandma hated the resulting stain for the next ten years until they stripped the wallpaper. And that taught us kids about pressure gradients.

    The other point is that I have noticed that right before dawn the temps drop…even in our summer…or winter. And I mean enough change that you can feel it right before the sun comes up. I noticed the same thing when milking the cow at 5 a.m. when I was a kid living in the Sierra Mountains of central California.

    I conjecture it is a result of the sun-warming expanding the air as the sun advances and that tends to push a wave before it of unheated air. Since I lived in the mountains…and now live near mountains… I think it is the mountain air arriving. In the summer I like to walk at 5 a.m. due to the very high temps and humidity here in Sonora.

    Just a couple of things I have noted about weather in my 66 years.

    1. Marjory Wildcraft says:


      thanks so much for that. Does sassafras grow in Mexico? I thought that was an Eastern US Appalachian type plant. But I may be mistaken.

      You are reminding me that here, our local organic gardening hero, John Dromgoole, often speaks that the sage will bloom just before a rain. I’ve have one right by my gate and it does seem to preict rain by a few days.

      Now, what we really need to know is how to attract rain…

  • Evelyn Y. says:

    Well, I wish I could remember the name of the book that I read a few years ago, all about Texas weather and how the old timers used animal, vegetation, etc. to tell the weather. I did take away that when cows lie down along the fence line, it usually means big weather change. It is fascinating! Thanks!

    1. Marjory Wildcraft says:

      Evelyn, if you recall the title of that book, please post it for us.

      Thanks, Marjory

  • melanie says:

    Why is high pressure “dirty” and low pressure “clean”? That sounds opposite of what I would expect. High pressure, to me, means clear skies.

  • Lauralee Hensley says:

    Well in the state I live, in the winter months if the sky gets a very light blue, almost no blue at all as it is such a pale blue and maybe the slightest hint of green, we can pretty much plan on a blizzard coming in the next day to maybe the next day and a half. Some around these parts actually call it blizzard blue.

  • Lauralee Hensley says:

    So what is the American Indian thing of counting out the rings circling the moon to the ring that looks copper-like. Usually around here if you count out to that ring you can plan on either rain or snow that many days out. Say if you count out three different colored rings around the moon to the sort of copper colored one, than in three days expect humidity in the form of rain or snow. Anyways pretty accurate around here. Has anyone else heard of this?

  • Kelly says:

    My grandfather was a dairy farmer, so he had to be able to do a it of weather reading. He always said that clouds that looked like mare’s tails meant rain. And I think something about a lot of spiderwebs in the grass in the morning meaning it would be a clear day.

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