This Week's Update Includes:

• News: A Critical Time is Passing
• Slideshow: Temperature and Survival
• The Migration: Maps and Journal

"The really critical time for the monarchs is January and early February," says Dr. Lincoln Brower. "The lethal combination for the butterflies is to be wetted by a winter storm, and then subjected to freezing temperatures caused by intense radiant heat loss when the sky clears."

Living in a Cold Climate
People are welcoming the recent change to warmer temperature says Estela Romero. Winter nights get cold because houses are not heated. When going to bed at night, people wear warm pajamas and pile blankets on their beds.

• In this week's report, Estela visits the town market where children often help with the family business.

Today's Temperatures?
How are temperatures affecting monarchs today? You can track real-time weather information at the monarch overwintering region. Watch how temperatures change as spring migration approaches:

• Today's Temperatures

• Slideshow: Temperature and Survival

Slideshow