Annual Weather Summary: November 2017 to October 2018 Winter will be colder than normal, especially in the south, with the coldest periods from late November into early December and in late December, mid-January, and early February.
It is an adjective that serves to modify nouns. Nouns modified by every are singular and must be written in such a manner. For example: Every <person> involved in the crash died. The reason for this singularity is because the word every literally means each, and refers to a single entity. Moreover, another reason for this is every is derived from the terms everything and everyone.. Notice here that obviously thing and one are singular objects.
How to treat a country name that has a plural meaning. There are many cases where an entity that's made up of plural words is singular. Obviously, the United States of America is a single entity, so has is right. This isn't an exception; this is the rule. Unlimited Designs, a Delaware corporation, has gone out of business. CSS (Cascading Style Sheets) is a great way to style your webpages.