Dog Days of Summer: The hottest days of the summer.
It is because it this time the star Sirius is seen very well, and this star is in the constellation of "Great Dog"
I like your description.
The day has eyes, the night has ears.
"The Night has a Thousand Eyes", Bobby Vee, 1963
Nice song, but a cheesy video:)
C'est le jour et la nuit (it's night and day) = is used to compare 2 persons or 2 objects. It means that they are opposite.
Pierre et son frère, c'est le jour et la nuit. Pierre est très intelligent mais son frère est stupide. = Pierre and his brother, it's night and day. Pierre is very smart but his brother is stupid.
In spanish: 'Son como el día y la noche = Son como el perro y el gato = Como ir del cielo al infierno...' two people who are opposite... but they have a strong relationship (they are partners or a couple or family...) for ever.
In French "être comme chat et chien" (ser como el perro y el gato) has a different meaning. It means that the persons can't bear, stand each other. When they meet, they fight, they argue (not really a strong relationship. ^_^).
"C'est le jour et la nuit" ; It doesn't necessary mean that the 2 persons are enemies. This saying can be used for persons or for object or anything else.
I'm from Brazil. In my country, when someone says "Eu tive um dia de cão" "I had a dog day", it means the day was very tiring or full of frustations. I think it's very different than that one.
are like oil and water........ are like the sun and rain....