Home > Science Fact Finder > Weather and Climate - What Are Sundogs And Moon Dogs?

1. Printable Version
2. Download PDF
3. Cite this Page

What are sundogs and moon dogs?

Sundogs, also called "mock suns" or "parahelia" (Greek for "beside the sun"), appear as one or two patches of light on either or both sides of the sun. Sundogs give the illusion that there are two or three suns in the sky. Sundogs may be white or colored, and often appear along the path of a 22 degrees halo (a thin ring of light around the sun).

These patches of light are occasionally seen around a very bright, full moon. In that case, they are called moon dogs.

Sundogs are produced by the refraction (bending) of sunlight through relatively large ice crystals. Sundogs and moon dogs form only in cold regions.

Sources: Ahrens, C. Donald. Meteorology Today: An Introduction to Weather, Climate, and the Environment, 5th ed., pp. 99-100; Engelbert, Phillis. The Complete Weather Resource, vol. 2, pp. 329-31.

Join eNotes

The above is a free excerpt. Get total access to this content with the:

eNotes Pass

1. Atmospheric Basics
   1. What is barometric pressure and what does it mean?
   2. What are the highest and lowest recordea temperatures on Earth?
   3. What is the Coriolis effect?
   4. Why are the horse latitudes called by that name?
   5. What are jet streams and when were they discovered?
   6. What is the dew point and how does dew form?
   7. When does frost form?
   8. What is the heat index?
   9. How much humidity should be maintained in the house during winter?
   10. What is meant by the windchill factor?
   11. When and by whom were clouds first classified?
   12. What are the four major cloud categories, based on height in the sky?
   13. What is the Beaufort Scale?
   14. Is Chicago the windiest city?
   15. What is a chinook?
2. Precipitation And Thunderstorms
   1. How does snow form?
   2. How much water is there in an inch of snow?
   3. Is it ever too cold to snow?
   4. Can two snowflakes be alike?
   5. What is the difference between freezing rain and sleet?
   6. When and where do thunderstorms occur in the United States?
   7. Where is the rainiest place on Earth?
   8. How hot is lightning?
   9. How is the distance between lightning and an observer calculated?
   10. What is ball lightning?
   11. What color is lightning?
   12. How large can hailstones become?
   13. How many volts are in lightning?
3. Tornadoes And Hurricanes
   1. Which month is the most dangerous for tornadoes in the United States?
   2. What is the Fujita and Pearson Tornado Scale?
   3. How are hurricanes classified?
   4. Which U.S. hurricanes have caused the most deaths?
   5. What were the deadliest and costliest natural disasters in United States history?
   6. How do hurricanes get their names?
4. Optical Effects
   1. What is the order of colors in a rainbow?
   2. What is a halo?
   3. What are sundogs and moon dogs?
   4. When does the green flash phenomenon occur?
   5. What is Saint Elmo's fire?
   6. How does an airplane produce a glory?
5. Forecasting And Climate
   1. When did the first television and radio weather forecasts take place?
   2. How accurate are forecasts?
   3. What is nowcasting?
   4. What is a radiosonde?
   5. Can groundhogs accurately predict the weather?
   6. Is the world actually getting warmer?

1. Global Warming