The sun is out, the flowers are blooming and you've been working out for months to look your best. You know what that means — it's hoodie season.

At least, it is if you're Mark Zuckerberg, king of hoodies. The Facebook CEO turns 30 years old Wednesday, so we compiled a fashion guide worthy of his reading list.

The hoodie is a staple of fashionable techie closets, as necessary to a wardrobe as blue jeans, black turtlenecks and semi-ironic calculator watches. Exotic, mysterious, zippable — hoodies are so in right now. Unfortunately, not many truly understand the subtlety of hoodie fashion. If we've learned anything from Zuckerberg, it's that hoodie wearing isn't all just "zip up when cold" or "unzip when hot." Believing so could be the difference between success or failure in the startup world.

Luckily, we've compiled a Zuckerberg-inspired fashion guide to your sweatshirt summer wardrobe. From the boardroom to the workout, we have you covered on the complexities of the hoodie.

The Mark Zuckerberg Guide to Hoodie Fashion

1. The business casual 3/4 zip

Nothing says "I am comfortable at my place of work" quite like the 3/4 zip. Stylish, playful, modern. Very 2014.

Image: Mashable, Will Fenstermaker
2. The important business full zip

Powerful, firm and commanding attention, the full-zipped hoodie really shouts, "Please pay attention to the following two hours of PowerPoint slides." Numbers and charts are involved, and you probably have a laser pointer. If nervous about public speaking, try to draw strength from knowing how good you look.

Image: Mashable, Will Fenstermaker
3. The Silicon Valley job Interview

Congratulations on receiving an interview at a promising startup! While selecting your hoodie style, it's important to first research the company. How do its founders wear their hoodies? Plan accordingly.

Image: Mashable, Will Fenstermaker
4. A job interview anywhere else

You should not be wearing a hoodie.

Image: Mashable, Will Fenstermaker
5. The first date 7/8 zip

For a first date, you want your hoodie to reflect both comfort and conservatism. You're here to talk about your favorite alternative rock bands and admire each other's hoodies, nothing more.

Image: Mashable, Will Fenstermaker
6. The third date 1/3 zip

Things are going great in your love life, and it's time your hoodie reflected that. Don't be afraid to get crazy: Let your undershirt shine with a stylish 1/3 zip.

Image: Mashable, Will Fenstermaker
7. The workout full zip

When working out, you want to trap your body heat to maximize perspiration, so let's get those hoods up. We recommend pushing up your sleeves to intimidate fellow joggers with your forearms.

Image: Mashable, Will Fenstermaker
8. The resting hoodie unzip

You've had a long day. Kick back, take a load off and continue illogically refusing to remove your hoodie. Surround yourself with dozens of 100-calorie snack packs and see how long you can watch House of Cards without blinking.

Image: Mashable, Will Fenstermaker