I am so sorry guys, there was a bug in my code!

The problem was, that when a post is edited, it appears again on the blockchain, and so was counted again. So, some posts were incorrectly getting counted multiple times.

Here is the corrected graph and the corrected code:

from piston.steem import Steem
from steemapi.steemnoderpc import SteemNodeRPC
from collections import Counter
from datetime import datetime

counter = Counter()
postcounter = Counter()

start_block = 3145790 # 2016-07-12

rpc = SteemNodeRPC("ws://localhost:8090")
steem = Steem(node="ws://localhost:8090", nobroadcast=True)

counted = set()

for c in rpc.stream("comment", start=start_block):
    if c["parent_author"]:
        continue # only interested in posts, not comments

    identifier = "@" + c["author"] + "/" + c["permlink"]

    if identifier in counted:
        continue

    counted.add(identifier)

    try:
        post = steem.get_content(identifier)
    except:
        continue

    dt = datetime.strptime(post.created, "%Y-%m-%dT%H:%M:%S")

    print("\n" + str(dt))

    payout = float(post.total_payout_value.split(" ")[0]) + float(post.pending_payout_value.split(" ")[0])

    counter[dt.hour] = counter[dt.hour] + payout
    postcounter[dt.hour] = postcounter[dt.hour] + 1

    for i in range(24):
        if postcounter[i]:
            print(str(counter[i] / float(postcounter[i])))
        else:
            print("0")

This new graph is a little all over the place, but there are still some tendencies.

But I guess that timing doesn't matter that much after all, as posts can remain on the frontpage for a whole day or longer.

I did warn you that I could be wrong! Let's hope I'm right this time :)