also: にっこうさ
noun
diurnal temperature range; daily temperature range
Meteorological term for the difference between the highest and lowest temperature in a single day.
砂漠では日較差が非常に大きい。
In deserts, the diurnal temperature range is very large.
今日の日較差は15度に達した。
Today's daily temperature range reached 15 degrees.
年較差 refers to the annual range of temperature, while 日較差 is the daily range.
Compound of 日 (day) and 較差 (range, difference). The reading にちかくさ is the standard on'yomi combination; にっこうさ is a less common variant.