Nice post Christian, I just want to make an statement about this article... I'm Mexican and I think most of Mexicans would understand this phrases (we share a lot of history, of course), but they don't always have the same meaning! For example "ser muy rata" would mean a person who steals a lot... You don't need to rob a bank to be "un(a) rata", but still, I think the point is very clear! I just want people to know there are some differences between the Spanish (from Spain) and the Mexican Spanish, or the argentinian Spanish, or the colombian Spanish... and a really long etc.

Spanish is a really beautiful language and it is so rich because it has been adopted by different nations which have different coloquial expressions, so be aware which "kind" of spanish slang you'd like to learn, because if you go to Chile, they might not understand you if you say slang from Barcelona!

¡Mis mas cordiales saludos desde México!

Martín.

El día intercalar.

Nice job tooth!

I'm very impressed, I did not know some of this information... It was very educational! Your Spanish is pretty good! Just made a few mistakes but, don't we all?  Now, let's review some of them.

Note 1: It is possible to omit the article. Normally, if you start an article by writting the date you should use the article, for example, if your article starts like this:

"El 29 de febrero ..."

But if you start by using some introductory words, like you did starting with "Hoy, 29 de febrero". "El" it is no longer necessary.

Note 2: You already used "el mes" once, so you can omit it because it is already implicit in the sentence. It works just like this:

Por desgracia, este día adicional hace el mes de febrero el más frío del año en Canadá, un(?) día más largo

Unfortunately, this additional day makes the month of february the coldest of the year in Canada, a(?) longest day.

I wrote a question mark because I did not know if you meant that, or maybe you wanted to say "the longest day (of the year)" in which case it would be: "el día mas largo (del año)". 

Note 3: "Fuese" and "fue" are both indeed the verb "to be" but in different tenses. The preterito imperfecto form (fuese) is used to make statments that are fiction, they didn't happen so it is just a suposition. "Fue", instead, is a statement of something that "was" or "were" true, for example: He was a police officer. Él fue un oficial de policía. 

Note 4: "Añadir" is the verb "to add". When conjugated: They add... in Spanish it would be "Ellos añaden"

Note 5: There is a rule in Spanish grammar that says: "Y" cannot be find it before a word that starts with "i" or any other word that sounds like "i", instead it is used "e".

Anny questions? Don't hesitate to ask!

Good luck and keep it up! Regards, Martin.

Get confused* (Would be nice if we could edit our comments... LOL)

Thanks for the correction! Sometimes I got confused to find the proper words, guess I'm kind of rusty but this could be a good way to improve even English, I think it could be a good mediator if we have some communication problems.

I think I was kind of selective with the "native speakers" thing so it's a good idea to leave it "free entrance" to anyone who wants to learn Spanish and German. If you're interested maybe you can help finding other people to join the group