The basics: A retrograde occurs when a planet appears to be moving backwards from our vantage point here on Earth. It isn't actually moving backwards, it just appears that way. Mercury turns retrograde most often, about 3-4 times per year, and lasts for several weeks. When a planet retrogrades, what that planet rules tends to be thrown off, along with what the sign it's retrograding in rules.
With Mercury retrograde, we experience a shadow and a storm. The shadow period starts when Mercury first hits the point in the Zodiac it will turn direct at, and ends when it last hits the point in the Zodiac it will turn retrograde at. Most people don't feel the effects of Mercury retrograde until it enters the storm period though. The storm period of Mercury retrograde is when Mercury is moving at its slowest, less than 40 minutes per day. Mercury is a fast-moving planet and hates it when he's moving slowly. There's usually two storm periods, one around the time Mercury turns retrograde, and one around when it turns direct.
This Mercury retrograde begins on March 22nd at 2:34AM ET and ends on April 15th at 8:51PM ET. The shadow period is March 9th - May 3rd. The first storm period is March 18th - 29th, and second storm period is April 7th - 24th.
Hello Mercury madness! The first Mercury retrograde for 2018 starts in March, and this retrograde occurs entirely in fiery Aries. Mercury retrograde in Aries can bring some hot-hot-hot energy, as Aries is a high energy fire and cardinal sign. We can be more impulsive, impatient, wanting to jump into things without thinking, and this can get us in hot water in a flash, or cause some unexpected problems because we didn't think things through. Or didn't think at all! It's important to not give in to the impulsive energy, but we can feel like if we don't jump right away, we'll miss out. A lot of FOMO, but it may not be reality. Breathe!
Aries energy can be prone to accidents and injuries because of the impulsive energy, so we may see some extra accidents occurring around the world, especially with things where we didn't do our due diligence beforehand. Don't neglect the things that need maintenance!
Aries is also one of the signs of war, so we may see some extra violence around the world, an uptick in uprising somewhere, particularly with Uranus at the end of his time in Aries (though not aligning with Mercury during this retrograde, thankfully). Uranus will be at a critical degree in Aries (26 degrees) March 2nd - 22nd, so just before this retrograde starts, and we may be heading into the retrograde with some extra rebellion.
We do need to be mindful of our tempers, getting into fights and easily frustrated, and an outlet for energy can be key during this retrograde. Keep busy, and focus on something positive to direct the extra energy that can flare up. And be careful of what you say so you don't start a war!
On the upside, the retrograde doesn't start or end making a hard aspect to any of the other planets, BUT the Moon isn't going to be playing nice! The retrograde kicks off with the Moon in one of the signs Mercury naturally rules, Gemini (March 22nd 1:30AM ET - March 24th 4:52AM ET), and we can feel really off as it begins. Communication in particular, anything with technology/electronics, and we need to watch what we say, do some more listening, and be mindful of the impact of our words. Then when the retrograde ends, the Moon will be in Aries, the sign the retrograde is occurring in (April 13th 11:26PM - April 16th 4:50AM ET), and a new moon occurs in Aries on the last day of the retrograde, April 15th (9:57PM ET). So we can close the retrograde with some extra heat, extra impulse, and extra anger that needs to be tempered, and extra energy that needs a healthy and positive outlet.
The Moon will be in the other sign Mercury naturally rules, Virgo, March 28th (10:30AM ET) - 30th (1:52PM ET). This can be another little period during the retrograde when we may have a little extra struggle with the retrograde energy, and it may be focused more on daily lives, productivity, work, and the health of life.
But the most difficult time may come just after that, with the second full moon of the month - yep, March comes with another blue moon! This time on March 31st in Libra, which is the sign opposite Aries, the sign the Mercury retrograde occurs in. The full moon will be opposite the Mercury retrograde (though a little wide), and square (hard aspect) Saturn in Capricorn (slightly wide square Mars in Capricorn too, though too wide to also be square Pluto, who is much later in Capricorn). That full moon is so jam-packed with energy that we need to be extra, extra careful with. We need to find a way to use the energy without letting anything blow up - which might be difficult to avoid! We're missing a little Cancer action, so we need to work on bringing in some Cancer energy, and be more nurturing, supportive, giving comfort, and strengthening foundations. We need to come together emotionally, as one big family, and not get so lost in all of the external noise.
Mercury retrograde will be at a critical degree (13 degrees Aries) March 29th - 31st, and this may bring some difficult energy, and we may super impulsive, annoyed, and easily provoked. It goes into the Libra full moon, so that is really a hard time during this retrograde. Careful!
This Mercury retrograde will make 3 major aspects during the retrograde. He'll square Mars in Capricorn on April 4th (3:05AM ET), and this can be a time of major anger, frustration, annoyance. Keep busy, but also be mindful of accident/injury energy (so careful!). Mercury will also square Saturn in Capricorn on April 5th (4:22AM ET), and we can feel stuck, confined, restricted, limited, and this can make us more frustrated and annoyed. Don't give in to impulse, and try to find some space within limitations to breathe. Mercury will conjunct (align with) the Sun on April 1st (1:53PM ET), called the inferior conjunction, and this can usually be a positive aspect providing an opportunity to start something.
The retrograde begins at 16 degrees Aries, so those of you Aries born April 4th - 8th can feel the start of this retrograde most. The retrograde ends at 4 degrees Aries, so those of your Aries born March 23rd - 27th can feel the end of the retrograde most.
For the rest of you, check the house(s) Mercury will be retrograding in of your own natal chart, and any aspects Mercury will make during its retrograde to your natal planets, to fully understand how it will impact you personally.
If you have Mercury retrograde in your natal or progressed chart, you may not feel the worst of this. Those individuals generally don't experience the difficulties of the retrograde because it feels more natural to them. Of course, chances are everyone else around them doesn't have the same aspect, so they can still experience difficulties brought on by others.
Suggested Reading: The Mercury, Venus and Mars Retrogrades page for general interpretations