The bad weather, coupled with the late announcement, amounted to a lower turnout.
Protests were expected to be held in more than 1,600 places in 110 countries. The Hong Kong march will take place on Sunday.
Protest organisers are asking citizens to walk out of work ahead of a crucial United Nations summit and demand immediate action.
Protests in more than 1,400 cities expected to attract more than the 1.4 million people who took part on March 15 - but won't include Hong Kong students.
The international movement organised a protest in London last month where more than 1,000 environmental activists were arrested.
The TV scientist appeared on political satire programme 'Last Week Tonight' to berate people who refuse to act on climate change.
A miscommunication meant student organisers cancelled march; they now hope to be able to protest this month.
Human activities such food production and energy consumption are major causes of why the Earth is in such bad shape.
The vote to declare the emergency does not legally force the government to act, but shows how important the issue is.
Students are divided on the details of a climate march due to take place on May 26.