All three incidents in which Merkel's whole body shook in public took place as she stood still without talking, and ended immediately once she started walking.
The German chancellor was seen in a similar situation on June 18, during a military parade attended by Ukrainian President Volodymir Zelenskiy and once again on June 27, alongside German President Frank-Walter Steinmeier during an European Union parliament appointment ceremony.
Merkel made a decision to seek a fourth term in office only after long reflection, and said in November 2016 she was seeking to stay on "if health allows".
This happened when she welcomed the new Ukrainian President Volodymyr Selensky in Berlin. Temperatures were much cooler that day, as they were on Wednesday.
On Wednesday, Chancellor Merkel cited that the psychological impact of the first incident was responsible for her trembling for the third time.
"Merkel is the guarantee of stability and many people want her to serve a full term", he told Reuters.
She clarified, "I said recently that I am in a phase of processing the last military honors with President Zelenskiy". She said after the incident that she was feeling fine and that there was no reason for concern.
"Everyone should do that and recognize that a mega-stressful job can also leave its mark", she added.
Because the health of public figures in Germany is regarded as a private matter, the country has very strict laws on the release of their health information. She has rarely cut back on her work schedule significantly, except once when she cracked her pelvis while cross-country skiing.
Still, the repeated bouts of shivering renewed pressure on Merkel to open the books on her state of health and raised concerns about her ability to continue governing.
"My comments on this are done today, and I think my statement that I am fine can find acceptance", she said.
"Just like how it has come, one day it will go away too", she said.
"I am very firmly convinced that I am entirely capable of performing", she added.
This is the third time in less than a month that the German chancellor, who is 64 years old and soon to be 65 next week, has appeared in public violently trembling.
Merkel, who has been leader of Europe's biggest economy for nearly 14 years, has always enjoyed relatively robust health.
She gave up the leadership of her center-right party after a pair of poor state election performances that followed a rocky start to her fourth-term government. She has shown no sign since of wanting to give up the chancellorship before her term is up.