Meaning of yì cháng:
yì cháng
异常
Adjective
unusual; abnormal
Jīntiān tiānqì fēicháng yìcháng, chūmén yào xiǎoxīn.
今天天气非常异常,出门要小心。
Today's weather is very unusual, be careful when going out.
Adverb
extremely; exceptionally
Jīntiān tiānqì yìcháng liángshuǎng, zhè zhēn shì nándé de hǎo rìzi.
今天天气异常凉爽,这真是难得的好日子。
Today's weather is exceptionally cool, this is truly a rare good day.