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 because it's nearest to us, 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.
The shadow of this Mercury retrograde begins June 9th and ends August 3rd, lasting eight weeks. The exact retrograde begins June 26th at 9:08AM ET and ends July 20th at 2:22PM ET. While there usually is two storm periods, this retrograde will be one long, never-ending storm period from June 18th - July 28th. Not fun!
When we don't leave the storm period, we don't really get a break from the wackiness of Mercury retrograde. Usually, there's a period in the middle of it where things seem to slow down, and you get a chance to catch your breath before the next storm period begins. Not so with this retrograde. I've got one word for you: relentless.
This retrograde occurs entirely in water sign Cancer. Cancer rules the home, so we could see lots of bad things happening to homes. Your neighborhood is built on an ancient burial ground. A sinkhole erupts in your living room. Nests and swarms of animals infiltrate neighborhoods. Cancer also rules the weather, so it could be a lot of weather events happening that does widespread damage to homes. Make sure your insurance is up to date.
We could hear bad news about real estate, some sort of setback with the housing market, which isn't good considering how bad it's been, but that should change soon after this retrograde is over. Some sort of housing scam could come to light, or more problems with mortgage lenders.
We may have domestic issues that come up that shock us, anger us, upset us, frustrate us. We feel neglected or ignored by our governments, and don't feel like they understand what's really important to us. Domestic issues may be put aside so focus can be put on international issues and the problems facing other countries.
Cancer also rules family, and we could hear something troubling about the state of family, some new wave of wacky parenting, and be more critical of parents, especially mothers. Someone could make headlines for something she's done as a mother, good or bad. We struggle to be as supportive and encouraging as we should be of one another, and feel more isolated and alienated from our families, whether they be our blood relatives or broader, cultural families/countrymen.
To add insult to injury, the turn direct of this retrograde will be square (difficult aspect) Uranus in Aries, which will be stationary (not moving) because it just turns retrograde 3 days prior. Unexpected bad news and developments? Plans suddenly falling apart at the last minute? Out of control rebellion of the youth? And technology could take a hit since both Mercury and Uranus rule technology. Some sort of super hacking case?
On the upside, quickly after this retrograde ends, we put the pieces of life back together again quite well with both Mars and Jupiter in Cancer. That'll help to make everything all better again. We'll be all, wow, can you believe how bad it just was and how quickly it went away? Rad.
The turn retrograde begins at 23 degrees Cancer, so those of you Cancereans born July 14th - 17th may feel the turn retrograde most. The turn direct occurs at 13 degrees Cancer, so those of you Cancereans born July 3rd - 7th may feel the turn direct 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.