How Chicago's times are computed
For Chicago (41.83° N, 87.75° W) Hourora computes the sun's position for each date and solves for each prayer: Fajr 15°, Isha 15°. Asr uses the standard shadow rule. The times are shown in Central Daylight Time, daylight saving included.
The default is the method usually published in United States: Islamic Society of North America (ISNA). You can choose another method, the Asr rule and the high-latitude rule above; the choice is saved on this device.