Weather Control
There is some type of weather that you absolutely dislike. I hate rain. Snow I love, and sleet I can tolerate, but rain, I hate. If I could, I would eliminate rain all together. However, I am not a great fool, I know how important rain is for sustaining life, especially my own. Instead of eliminating rain, if I had a weather control device, I could turn off the rain if I had something planned for the outdoors, or even for a few minutes as I need to be outdoors. Making life for the Evil Overlord, me, so much more enjoyable.
As a side benefit of a weather control device, it can be used as or in conjunction with a dooms day device. It can also be used to target parts of the world to make them fruitful once more. There are many deserts which get very little moisture which could be turned into fertile soil. There are other parts that get too much rain, and they can be toned down a lot. So the evil overlord would not be the only one benefitting from a weather control device.
It is too important, you must be able to control the weather. It works like this, you have this device, and it controls the weather. It is simple. The design is beautiful. Everyone will want one, and only one will have it.
I want one!
I don’t mind the changes in the weather system… but when it’s over 100F at night, something’s got to change. It would be most ideal to have less extreme temperature changes. Perhaps, with such a weather control device, different areas should be designated as particular climates ranging within 20 degrees from summer to winter. Undoubtedly, you would place snowy mountainous regions nearby to supply an ample playground for winter sports enthusiasts, and warm areas for summer sports enthusiasts.
When you are Evil Overlord, you may do as you wish.