Use photoperiod to estimate latitude. Calculate photoperiod using sunrise/sunset data.

Sunrise/sunset data from the 10 Mystery sites will be posted here weekly on these dates. Record and graph the photoperiod for each site.

• January 28
• February 4
• February 11
• February 18
• February 25
• March 4
• March 11
• March 18
• March 25
• April 1
• April 8

Your Local Data

Look up your own sunrise/sunset for the dates above. Calculate, record and graph your photoperiod. How does it compare to the Mystery Sites?

Narrow the search from continent to country to city. Clues will be posted weekly on these dates.

• March 18 (continent/region)
• March 25 (country)
• April 1 (state/province)
• April 8 (city/town)