Just to give your post a more fair response.
To say the night does not get as dark at night in the summer is an understatement. It DOES NOT GET DARK AT ALL.
Only as the year gets closer to autumn does it even lessen any brightness at all.
God's word was clear in Genesis. He called light day and the darkness night. It is not night if it is not dark. Period.
All in all, these verses says IT IS FOR ISRAEL:
Exodus 31:12-18 And the LORD spake unto Moses, saying, Speak thou also unto the
children of Israel, saying, Verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the LORD that doth sanctify you. Ye shall keep the sabbath therefore; for it is holy unto you: every one that defileth it shall surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from among his people. Six days may work be done; but in the seventh is the sabbath of rest, holy to the LORD: whosoever doeth any work in the sabbath day, he shall surely be put to death. Wherefore the children of Israel shall keep the sabbath, to observe the sabbath throughout their generations, for a perpetual covenant. 17
It is a sign between me and the children of Israel for ever: for in six days the LORD made heaven and earth, and on the seventh day he rested, and was refreshed. And he gave unto Moses, when he had made an end of communing with him upon mount Sinai, two tables of testimony, tables of stone, written with the finger of God.