The declaration of a La Nina is made after five months of three month periods of La Nina conditions. Just because (is this your source?) http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.shtml says "The weekly Niño indices were variable during the month, with values near -0.5° C during the past week in the Niño-3.4 and Niño-3 regions" does not warrant using a title "La Niña update: She’s back!" Check out Google News - there are many headlines claiming we are in a La Nina. We aren't. I don't know how many trace their headline back to yours, but it would be nice if you can try to stop it. I'll try to help on another climate blog. https://news.google.com/news/story/dVzWP-trFGJEamMgxFvpRhLTnW6iM?ned=us&gl=US&hl=en may show what I mean at Google news.