A strong, rapidly intensifying El Niño—already producing Niño 3.4 anomalies near +2.8 °C and forecast to peak near +4 °C in November—combined with the long-term warming trend has driven September 2026 global temperatures toward the second-highest monthly value on record. Year-to-date 2026 ranks second-warmest behind 2024, while August 2026 set or tied the all-time hottest month benchmark in multiple datasets; September is tracking roughly 0.1–0.2 °C below the 2023 September peak yet well above prior years. Official forecasts from Copernicus, NOAA, and Berkeley Earth indicate the month will almost certainly finish among the top three Septembers, with market-implied odds reflecting the narrow gap to first place and limited downside risk from model consensus. A faster-than-expected El Niño heat release or revised observational adjustments could still lift it to first, while an unusually sharp late-month cooling would be required to drop it lower.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedSeptember 2026 1st, 2nd, or 3rd hottest on record?
September 2026 1st, 2nd, or 3rd hottest on record?
2nd hottest 97.0%
4th or lower 2.6%
1st hottest 1.7%
3rd hottest <1%
NEW
NEW
Sep 30, 2026
1st hottest
2%
2nd hottest
97%
3rd hottest
1%
4th or lower
3%
2nd hottest 97.0%
4th or lower 2.6%
1st hottest 1.7%
3rd hottest <1%
NEW
NEW
Sep 30, 2026
1st hottest
$1,322 Vol.
2%
2nd hottest
$1,072 Vol.
97%
3rd hottest
$893 Vol.
1%
4th or lower
$958 Vol.
3%
This market will resolve based on the data for the Global Land-Ocean Temperature Index for September 2026 versus the data points available for all other Septembers on record.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.A strong, rapidly intensifying El Niño—already producing Niño 3.4 anomalies near +2.8 °C and forecast to peak near +4 °C in November—combined with the long-term warming trend has driven September 2026 global temperatures toward the second-highest monthly value on record. Year-to-date 2026 ranks second-warmest behind 2024, while August 2026 set or tied the all-time hottest month benchmark in multiple datasets; September is tracking roughly 0.1–0.2 °C below the 2023 September peak yet well above prior years. Official forecasts from Copernicus, NOAA, and Berkeley Earth indicate the month will almost certainly finish among the top three Septembers, with market-implied odds reflecting the narrow gap to first place and limited downside risk from model consensus. A faster-than-expected El Niño heat release or revised observational adjustments could still lift it to first, while an unusually sharp late-month cooling would be required to drop it lower.
This market will resolve based on the data for the Global Land-Ocean Temperature Index for September 2026 versus the data points available for all other Septembers on record.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.
Market Opened: Aug 28, 2026, 11:14 AM ET
Volume
$4,246End Date
Oct 1, 2026Market Opened
Aug 28, 2026, 11:14 AM ETResolver
0x69c47De9D...This market will resolve based on the data for the Global Land-Ocean Temperature Index for September 2026 versus the data points available for all other Septembers on record.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.A strong, rapidly intensifying El Niño—already producing Niño 3.4 anomalies near +2.8 °C and forecast to peak near +4 °C in November—combined with the long-term warming trend has driven September 2026 global temperatures toward the second-highest monthly value on record. Year-to-date 2026 ranks second-warmest behind 2024, while August 2026 set or tied the all-time hottest month benchmark in multiple datasets; September is tracking roughly 0.1–0.2 °C below the 2023 September peak yet well above prior years. Official forecasts from Copernicus, NOAA, and Berkeley Earth indicate the month will almost certainly finish among the top three Septembers, with market-implied odds reflecting the narrow gap to first place and limited downside risk from model consensus. A faster-than-expected El Niño heat release or revised observational adjustments could still lift it to first, while an unusually sharp late-month cooling would be required to drop it lower.
This market will resolve based on the data for the Global Land-Ocean Temperature Index for September 2026 versus the data points available for all other Septembers on record.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.
Note: If September 2026 is tied for first, second, or third hottest with another year, it will qualify for the bracket it ties with.
The primary resolution source for this market will be the figures found in the table titled "GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius" under the column for the relevant month (https://data.giss.nasa.gov/gistemp/tabledata_v4/GLB.Ts+dSST.txt). If NASA's "Global Temperature Index" is rendered permanently unavailable, other information from NASA may be used.
If no information for September 2026 is provided by NASA by the last day of the following month, 11:59:59 PM ET, a consensus of credible sources will be used to resolve this market.
Volume
$4,246End Date
Oct 1, 2026Market Opened
Aug 28, 2026, 11:14 AM ETResolver
0x69c47De9D...A strong, rapidly intensifying El Niño—already producing Niño 3.4 anomalies near +2.8 °C and forecast to peak near +4 °C in November—combined with the long-term warming trend has driven September 2026 global temperatures toward the second-highest monthly value on record. Year-to-date 2026 ranks second-warmest behind 2024, while August 2026 set or tied the all-time hottest month benchmark in multiple datasets; September is tracking roughly 0.1–0.2 °C below the 2023 September peak yet well above prior years. Official forecasts from Copernicus, NOAA, and Berkeley Earth indicate the month will almost certainly finish among the top three Septembers, with market-implied odds reflecting the narrow gap to first place and limited downside risk from model consensus. A faster-than-expected El Niño heat release or revised observational adjustments could still lift it to first, while an unusually sharp late-month cooling would be required to drop it lower.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
Beware of external links.
Beware of external links.
Frequently Asked Questions