Korea Fall Foliage Map 2026: How Peak Dates Are Set

Autumn leaves on a Korean mountain slope, illustrating the 2026 peak foliage forecast dates by region

Korea does not publish one autumn foliage forecast. It publishes at least three, built on different definitions of "peak," and they do not always give the same date. In 2026, the Korea Forest Service (산림청), the Korea Meteorological Administration (기상청, KMA), and the Korea Tourism Organization (한국관광공사) with the Korea National Arboretum (국립수목원) each released their own numbers. This guide explains what each one measures, lists the 2026 dates, and shows how to combine them into a trip plan.

Three Forecasts, Three Definitions of "Peak"

The word Koreans use is jeoljeong (절정), literally "the summit" or "the height." What counts as the height depends on who is counting.

Source	What it measures	Definition of peak
KMA (기상청)	21 named mountains, observed every year	About 80% of the mountain turned; "first foliage" (첫 단풍) is about 20%
Korea Forest Service (산림청)	A national peak-forecast map for mountains and tree species	Described in press coverage as roughly 50% turned
Tourism Organization + National Arboretum	Peak dates by tree species at arboretums in six regions, plus 36 recommended sites	Species-level dates from citizen observations

The KMA definition comes from the agency's own regional webzine, which states that it tracks the start and peak of foliage on 21 mountains each year. The 50% figure for the Forest Service map comes from SBS Biz's report on the September 22 release, and a Maeil Shinmun report likewise describes peak as the point when more than half the leaves have changed. I did not find the Forest Service's own release text, so treat the 50% figure as the press's description of the agency's standard.

This matters in practice. A mountain that is "at peak" by a 50% rule can still look half green by the 80% rule, so two correct sources can differ by days. If one site says October 19 and another says October 20 for the same mountain, the cause is usually the source, not an error.

The Forest Service Map: Mountain by Mountain

The Forest Service's 2026 peak-forecast map, as reported by SBS Biz, expects nationwide peak in the second half of October and gives dates for four major mountains:

Mountain	Forecast peak	Region
Seoraksan (설악산)	October 20	Gangwon, northeast
Songnisan (속리산)	October 28	North Chungcheong, central
Naejangsan (내장산)	November 4	Jeolla, southwest
Hallasan (한라산)	November 6	Jeju

By species, the same report lists ginkgo at October 30 and maples and oaks at October 31. It adds that this year's timing is about 0.8 days later than the five-year average, which the Forest Service links to climate change. Some outlets, including Wikitree, gave Seoraksan as October 19, so check the date against the source you read.

The south-to-north gap is large. Maeil Shinmun notes that color moves from Seoraksan in Gangwon down to Naejangsan in Jeolla over roughly two weeks. For travelers, that is useful: a single trip can cover two stages of color if you move south as the month goes on. Our Seoraksan autumn foliage guide covers the northern end of that sequence.

The Tourism Map: Peak Dates by Tree Species

On October 8, 2026, the Korea Tourism Organization and the Korea National Arboretum published the "2026 Autumn Foliage Map" (2026 단풍지도) on the national tourism site Visit Korea (대한민국 구석구석), according to Financial News and Kyunghyang Shinmun. It splits the country into six regions and recommends 36 sites.

The unusual feature is that dates are given per species, because maples, ginkgo, and oaks do not turn together. Based on Wikitree's breakdown of the map, the forecasts are tied to named arboretums:

Region	Maple	Ginkgo	Oak
Seoul metropolitan area (Korea National Arboretum)	Oct 29	Oct 31	Nov 2
Gangwon	Oct 28	Oct 27	Oct 31
Chungcheong (two sites)	Oct 27 / Nov 2	Nov 4 (one site)	Nov 3 (one site)
Gyeongsang (Daegu arboretum)	Nov 6	Nov 4	Nov 14
Gyeongsang (Gyeongnam arboretum)	Nov 8	Not listed	Nov 16
Jeju (Hallasan Arboretum)	Nov 19	Nov 16	Nov 16

For Jeolla, the same report gives ranges rather than species dates: November 1 to 4 at one arboretum and November 9 to 16 at another, varying by species. Read the table as a guide to when each tree type peaks in each region, not as a promise for a specific park.

Only seven of the 36 sites appear in the coverage I could access: Incheon Grand Park (인천대공원), Goseokjeong in Cheorwon (철원 고석정국민관광지), Sapgyoho in Dangjin (당진 삽교호), Munggwang Reservoir in Goesan (괴산 문광저수지), Changpo Garden in Geochang (거창창포원), Metaprovence in Damyang (담양 메타프로방스), and Ttarabi Oreum in Seogwipo (서귀포 따라비오름). The full list is on the Visit Korea site. Most of these are lakes, gardens, and open hills rather than the famous national parks.

Where the Data Comes From: Citizen Observers

The tourism map's predictions rest on the Arboretum's Plant Phenology Observation Project (식물계절관측 프로젝트), in which 829 citizen scientists contributed observations this year. Phenology means the study of seasonal timing in plants. According to SBS Biz, the Forest Service and the Arboretum have accumulated long-term phenology records since 2009.

The public side is open to anyone. A 2025 report described a mobile phenology platform, launched September 25, 2025, where participants recorded foliage changes on a street tree, a park, or a famous site, running October 1 to November 19. It was the second such citizen program after a spring cherry-blossom edition. For 2026, Maeil Shinmun reports that the Arboretum's peak-search service opened on September 29 and was based on 2,806 citizen observations.

KMA's approach is the opposite: a fixed set of 21 mountains watched by trained observers with the same viewpoints each year. The webzine describes a Gyeryongsan example in which observers check three specific maple trees and a wide view of the slope. The result is consistent year-to-year data for famous mountains, while the citizen system covers many more places.

2026 So Far: First Foliage and Timing

This year's first foliage at Seoraksan was recorded on September 28, according to the Wikitree report on KMA and Kweather data. That is four days earlier than last year and in line with the normal date. KMA's average first-foliage date for Seoraksan is September 28 and last year's was October 2, per a Supple News report. Peak typically follows about two weeks after first foliage, which is why the forecasts for Seoraksan land around October 19 and 20.

SBS Biz also reported that the first citizen-recorded color this year came from Jeombongsan (점봉산) in Gangwon on September 14, before KMA's first-foliage date. That is a good example of why the systems differ: a citizen sighting of one turning tree is not the same as 20% of a mountain.

How to Use the Forecasts for a Trip

Choose by tree, not just by place. If you want gold ginkgo avenues, use the ginkgo column. For red maples, use the maple column.
Treat peak as a window. These are estimates, and weather can move them. Plan for several days either side.
Go north first, then south. Late October suits Gangwon and the Seoul area; early to mid-November suits Gyeongsang and Jeolla; mid-November suits Jeju. Southern heritage cities such as the one in our Gyeongju travel guide fall in the later window.
Check live data before you leave. The Arboretum's peak-search service and KMA's mountain observations update as the season moves.

FAQ

When is peak foliage in Korea in 2026?
Forecasts put peak in the Seoul area and Gangwon in late October, Gyeongsang and Jeolla in early to mid-November, and Jeju in mid-November. The Forest Service forecasts Seoraksan on October 20 and Naejangsan on November 4.

Why do Korean foliage sources give different peak dates?
They use different definitions. KMA counts about 80% of a mountain as peak, press coverage describes the Forest Service standard as about 50%, and the tourism map gives separate dates for maples, ginkgo, and oaks.

Where can I find the full list of recommended foliage spots?
The 2026 Autumn Foliage Map on Visit Korea (대한민국 구석구석) lists all 36 recommended sites across six regions. It was released by the Korea Tourism Organization and the Korea National Arboretum on October 8, 2026.

Verified as of October 16, 2026. All peak dates are forecasts and can change as the season develops. The Forest Service's 50% peak standard and the arboretum-level dates are taken from press coverage of the releases, not from the agencies' own documents.