Heroku Scheduler timezone?

Question

What's the Heroku timezone for Scheduler? It says "UTC" but I'm not sure if that's correct. My tasks are starting at the wrong time despite converting the timezone correctly.

Thoughts?

Answer 1

This question's a bit old, but yes, Heroku Scheduler definitely uses UTC even if you specify a timezone in your app. I tested it with this code:

task :send_test_email => :environment do
  if Date.today.strftime("%A").downcase == 'monday'
    UserMailer.send_test_email(Time.now.strftime("%Z")).deliver
  end
end

I'm in Pacific time zone. I set Heroku Scheduler to run this every 10 minutes, and this email was able to send on Sunday night PST, which is Monday in UTC time. Also, the string I passed to the mailer,Time.now.strftime("%Z"), is set as the subject of the email which indeed read, "UTC"

One potential source of confusion is Daylight Saving Time. For example, UTC is always 8 hours ahead of Pacific Standard Time (PST - used for winter months), and 7 hours ahead of Pacific Daylight Time (PDT - used for summer months). So if your tasks are off by an hour, it could be you measured from the wrong UTC zone.