Here is a nice little collection of Navajo beliefs, superstitions, and taboos regarding the natural world and the weather.

• Do not look at clouds moving in the sky. If you do, you will be a slow runner.
• Do not eat when there is an eclipse, or you will have a swollen stomach or stomach problems.
• Do not sleep during an eclipse because your eyes won’t open again.
• Do not look at an eclipse, or you will go blind. This taboo is a fact. People can go blind by looking too long at an eclipse.
• Do not start a fire with a magnifying glass, or you will have a burning in your stomach.
• It is taboo to stand on high rocks. If traditional Navajos do, they say that the rocks will grow into the sky with them.
• Do not roll a rock from a mountain. The holy people put them there and it will be bad luck.
• The monsters that throw people off cliffs, are said to inhabit high places so they are best avoided!
• Do not use partly burned wood because it might be from a lightning struck tree. If you do it will cause illness or bad luck.
• Do not stand up when there is lightning. If you sit down it will go away.
• Do not yell when it is raining or you will be struck by lightning.
• Do not have a dog or cat in the hogan during a storm because it will draw lightning.
• Do not look lightning in the mirror because it will strike your hogan.
• Do not kill a nighthawk or you will be struck by lightning.
• Do not use aspen wood for a fire because it causes thunder and lightning.
• Do not stand by the loom when it is raining because the lightning will strike you.
• Do not weave when it is storming or it will cause lightning. This depends on the pattern being designed on the loom.
• Do not climb a tree when it is raining because lighting might strike the tree.
• Do not lean against a wall during a storm or the lightning will strike you.
• Do not ride a horse during a storm or you will be struck by lightning.
• Do not touch metal objects when it is raining because you will be struck by lightning.
• Do not wash your hair when it is raining because you will be struck by lightning.
• Do not eat an animal killed by lightning because you will be struck by lightning or get sick.
• Do not play around a lightning struck tree because you will get sick.
• Do not call the thunder’s name or the lightning will get you.
• Do not do a rain dance during a rainstorm because you will be struck by lightning.
• Do not lay facing the sky in a storm or the lightning will strike you.
• Do not eat corn when it is raining because lightning will strike you.
• Do not stare at the moon, or it will follow you.
• Don’t point at a rainbow with your finger. The rainbow will cut it off or break it.
• Do not watch a river flowing swiftly, or you will get dizzy and fall in.
• Don’t catch snow when its is falling, or it will keep falling and turn into deep snow.
• Do not hold out their hands when it is snowing because where your hand is will be how deep the snow will be.
• If you eat the first snow, you will become sick.
• Do not shake a flour sack in the winter, or the snow will get big and cause blizzards.
• Do not look at a shooting star unless you blow at it, or you will have trouble and bad luck.
• If you look at a falling star, there will be bad luck.
• Blindness is the punishment of looking to long at the sun. This punishment is a fact on life for all people.
• Don’t whistle too loud, or whistle for four days in a row. If you do, they say you will be calling up the wind
• Don’t throw rocks at a whirlwind. It will throw them back and chase you.
• Don’t call whirlwinds a name. Evil Spirits will get you.
• Don’t go into a whirlwind. It will effect your heart and carry you off.
• Dust devils are an evil wind that blows no one any good. They are animated by evil spirits.
• Don’t whistle or you will call up the wind!

Source: Navajo Central