I know the homeowner was just joking when he called the brown spots on his lawn “miniature crop circles caused by aliens. But he did have a point. Brown spots do seem to come out of nowhere and seemingly overnight (sans paranormal sound, I hope).
But there’s really no mystery to them, and with all this rain we’re having, it’s a good time to present you with facts. The “brown spots” in this particular case were actually identified as Brown Patch Fungus, a disease that favors high humidity coupled with temps of 85 degrees or higher in the day and 60 degrees or higher at night.
Since this “phenomenon” is mostly weather-related, there’s not much you can do to prevent it. However, your landscape maintenance company can adjust some of its cultural practices to limit further turf damage, including spot treating affected areas with a fungicide; lowering the amount of nitrogen and increasing the amount of potash in the fertilizer blends; and raising the height of cut slightly to put less stress on the turf
For those other, more infrequent times when the infection isn’t triggered by rainfall and instead by excessive irrigation, you can flex your human intellect and adjust your irrigation timers. Remember, turf surrounded by trees, shrubs and buildings will remain wet for extended periods of time due to reduced air movement and sunlight. Wise watering and good soil drainage will help reduce the incidence of brown patch.
Sorry I can’t help you with crop circles. That subject’s just too alien for me to even think about.