Set timezone when using published_at in routes

In my routes.yaml, I have this entry:

 /year/2020/:
    controller: channel
    filter: published_at:>='2020-01-01'+published_at:<='2020-12-31'
    order: published_at asc

But articles near limits (ie December 31st) are not returned by this code. I suppose it’s a timezone problem? How can I set the timezone correctly?

As my blog is in pacific time, I tried with:

    filter: published_at:>='2020-01-01T00:00:00-08:00'+published_at:<='2020-12-31T23:59:59-08:00'

But it’s not working.

Still struggling with this issue. Here is an example:

Here is the page corresponding to this filter:

  /year/2018/:
    controller: channel
    filter: published_at:>='2018-01-01'+published_at:<='2018-12-31'
    order: published_at asc

You will see that the last article of 2018 is not in the list

The publish date for this article is “2018-12-31 10:00 PST”.

Any idea?