The Korean court saw nothing odd in the sky, November 1808 to January 1809

The Royal Secretariat Diary gives the weather in Seoul every day. For lunar months 10 to 12 of King Sunjo's 8th year (about November 1808 to January 1809, the weeks after the eruption of about 4 December) every day was read: 82 percent clear, the rest overcast, rain or snow, with ordinary solar and lunar halos and fog. No dim, red or hazy Sun, no haze, no strange glows. The same months a year earlier were 74 percent clear. Two apparent hits in 1809 turned out to be a red ring around a prisoner's abscess and a speech about a rain prayer in a drought. Caveat: the daily line is short ('clear', 'overcast'), so a thin high veil might never be written down.

Third winter added when the download finished. Clear days in lunar months 10 to 12 (about November to January): 1807-08 81 percent (42 days read), 1808-09 85 percent (88 days, complete), 1809-10 89 percent (27 days read). No unusual sky words in any of the three. The eruption winter does not stand out. Some months in the comparison winters have gaps, either in the diary or in what the website returned. Data saved in sources/sjw_weather_1807-1810.jsonl.