iNaturalist Presents City Nature Challenge 2025 – Citizen Science Opportunity
April 25 - April 28
The City Nature Challenge (CNC) is a four-day bioblitz held every April. Cities around the world compete and collaborate to find species, make observations, and connect people with nature in urban areas.
How can I participate in the City Nature Challenge?
Mark your calendar for CNC 2025! Here are the key dates:
- April 25-28: Make observations
- April 29-May 4: Upload observations and help with identifications
- May 5: Results announced
You have two ways to participate:
- Take part in your city’s CNC event – Check this tentative list to see if your city is participating. If it is, you’re all set! Get ready to start making observations on April 25. Want to help promote the CNC in your city or hold an event? Projects are currently being added to the CNC 2025 umbrella project – once you see your city’s project, reach out to the project owners and let them know you’d like to help!
- Join the Global Project – If your city isn’t on the list, you can still take part in the CNC 2025 Global Project. This option is available for anyone, anywhere in the world. The Global Project will count toward the overall numbers of the City Nature Challenge!
Helping with identifications is also a great way to contribute! While observers must make observations in participating cities or join the Global Project, anyone can help identify species worldwide. Taxon experts and dedicated iNaturalist users play a huge role in refining observations and guiding new participants. Every identification helps move observations closer to research-grade status and lets new users know their contributions matter.