The purpose of this report is to find which U.S. cities have the most variety of weather. Each city will be given a score (Weather Variety Index) to determine which places have the most variety. The score is derived from 8 different categories. 6 of those categories are with 10 points, and two are worth 20 points.
Diurnal Temperature Variation - 10 pts
The difference in temperature between the warmest and coolest parts of the day. If a place is hot during the day and cold at night, that is more variety than somewhere with a small daily temperature range.
Annual Temperature variation - 10 pts
The difference in temperature between the warmest month and coldest month. A place with a big seasonal temperature difference has more temperature variety than a place where there is no distinct summer and winter.
Precipitation - 10 pts
Places with very little precipitation have mostly sunny days and therefore less variety than places with more precipitation.
Thunderstorms - 20 pts
Thunderstorm scores are doubled in the final counting because they bring a such a wide variety of weather. Hail, tornadoes, microbursts, mamatus clouds, wall clouds, lighting, sharp temperature drops, and many more exciting weather phenomena come from thunderstorms.
Wind - 10 pts
The wind category is based on both average wind speed and maximum gusts. Higher scores are given to places that frequently experience very strong wind.
Snow - 10 pts
Snow is another major part of weather. Snow is essential for a true winter and a complete variety of precipitation.
Lowest Score - 20 pts
The lowest score category is simply the lowest score in any of the previous categories. It is doubled in the final count because it is so important. Places that are severely lacking in any category lose almost 20 points here because they do not experience the complete range of weather. Places where the lowest score is very high have an abundant amount of all types of weather.
Low Precip + Low Temperature - 10 pts
The category is the average of the lowest score in the precipitation categories (precipitation, snow, and thunderstorms) and the lowest score in the temperature categories (diurnal temperature variation and annual temperature variation).
Total Score - 100 pts possible. The total score is simply the sum of the scores in the above categories.
Weather Phenomena Not Explicitly Included:
Some types of weather contribute to variety but were not explicitly used in determining the total score.
Hail is produced by strong thunderstorms, and is most common in areas with the most strong thunderstorms. It is very common on the lee side of the Rocky Mountains where elevations are still high (freezing level is not too high above the ground) but no barrier to Gulf of Mexico moisture. Cheyenne, WY averages more hail than any other place in the U.S. It is also in a location that recieves a lot of thunderstorms, strong wind, and a wide annual shift in temperature. Cheyenne thunderstorms are much more likely to produce hail than Miami thunderstorms because the freezing level is usually much closer to the ground in Cheyenne (among other causes). A good estimate of hail can be included with the 'thunderstorm' and 'annual temperature variation' categories (the greatest annual temp. variation is on the lee side of the Rockies where there is no barrier to cold or warm air).
Tornadoes usually occur in thunderstorms where there is a good clash of cold air (to the north) and warm air (to the south). They are also more frequent in the plains where there are no mountains to block these clashing air masses. The Oklahoma City area averages more tornadoes per square mile than anywhere else on earth. That is because it gets cold air from the north, warm moist air from the south, and is close enough to the Gulf of Mexico to have enough moisture for big thunderstorms. Tornadoes can also be included in the same two categories. It is not just a coincidence that the places with high Weather Variety Indecies happen to be in tornado alley.
Hurricanes mainly occur near the coast of the eastern (mainly southeastern) U.S. The conditions that are favorable for hurricane development are already included in the above categoroes 'thunderstorms' and 'precipitation'. The area with the most thunderstorms and precipitation is the southeast, which also recieves the most hurricanes. The variety of weather in a hurricane is primarilly two things: wind and precipitation. Both categories are there. Places that have been hit by hurricanes score high in the 'wind' category.
Sleet, Freezing Rain, etc.
These are implicity covered in the 'snow' category and also a little in the 'annual temperature variation' category.
There are more, but these are the most common. For an explanation of the scoring criteria, equations, weight of different categories, or any other questions send email to email@example.com. Any comments would be greatly appreciated.
More about this report is available in the following articles:
Jan. 6, 2000
Weirdest Weather in the USA - Springfield News-Leader (Front page story)
A Web site picks Springfield as the big city with the greatest variety of weather in the country
Jan. 7, 2000
Weather Variety - Interview with on 65 radio stations, from Missourinet. To hear the story and interview, Click Here.
Jan. 8, 2000
Wichita's Weather is Weird - Wichita Eagle
You knew it, but now it's a scientific fact: A researcher says the weather here varies more than it does almost anywhere else.
Jan. 21, 2000
Website Calls Springfield Weather Weirdest in the Nation
Diurnal Temp. Variation
Annual Temp. Variation
Complete Alphabetical List: Where does your city rank?