By using the lightning data from 2002 to 2004 in Suzhou, lightning characteristics such as monthly variation, daily variation, intensity of lightning current and lightning density are analyzed.

利用苏州地区2002 ~ 2004年闪电定位系统监测资料，分析了该地区地闪的月变化、日变化、强度、闪电密度等特征。

youdao

By Tompion's death, in 1713, daily variation was less than a minute, and by the late 19th century, marine chronometers were accurate to fractions of a second per day.

FORBES: Magazine Article

The National Statistics figures also showed there was a daily variation, something which has been seen since the 1970s, with more children born on weekdays compared to weekends and bank holidays.

BBC: Wintry nights spark summer births

Third, the child with bipolar disorder often has a daily variation: he becomes highly active at night and in the morning he is like a hibernating bear, all but impossible to get out of bed.

NPR: Excerpt: 'Delivered from Distraction'