The temperature outside is cool and the sky is blue.
temperature是名词，意为“温度”。当询问温度是多少时，要用what，不能用how much或how many;回答时可用“基数词+degree(s)”。
例:-What is the temperature today?今天的温度是多少?
-It's 30 degrees.30度。

On weekends, my family goes to the farm and picksapples.
(1)on weekends在周末，也可以表达为at weekends。例:We often play football on weekends.我们经常在周末踢足球。
(2)pick apples意为“摘苹果”，其中pick意为“摘(花、果实等)”。
例:The students helped the farmer pick fruit.学生们帮助这个农民摘了水果。

It is a great season for apple picking.
It is a great season for..这是..…….的好季节。for是介词，后面跟代词或动名词。
例:It is a great season for harvest.这是收获的好季节。