1. Check the grass for dew at sunrise.
2. Remember the rhyme: "Red sky at night, sailor's delight; Red sky at morning, sailors take warning."
3. Look for a rainbow in the west.
4. Detect which direction the wind is blowing.
5. Take a deep breath.
6. Check for humidity.
7. Watch the clouds.

via wikihow

1. Red or Pink Morning Sun or Sky
2. Red or Pink Evening Sun or Sky
3. Breakfast Rainbows
4. Tea Time Rainbows
5. Gray Morning Sky
6. Gray Night Sky
7. Rising Morning Mist or Haze
8. Low Sitting Clouds
9. High Sitting Clouds
10. No Morning Dew
11. Morning Dew
12. Silence'

full tips via ehow

1. Observe the air pressure.
2. Use the clouds.
3. Scrutinize the dew.
4. Search for a rainbow.
5. Identify the wind’s direction.

via howtodothings

1. Check the grass for dew at sunrise.
2. Remember the rhyme: “Red sky at night, sailor’s delight; Red sky at morning, sailors take warning.”
3. Look for a rainbow in the west.
4. Detect which direction the wind is blowing.
5. Take a deep breath.
6. Check for humidity.
7. Watch the clouds.
8. Observe animals.
9. Make a campfire. 
10. Look at the moon during the night.
11. Create your own prediction methods.
12. Look for pine cones

via dominica-weekly