ClimaBulletin

Mexico · Weekly

Week 39, 2026 (21–27 September)

Final Issued 2026-10-11 · version 3 · Baseline 1991-2020 · next update 2026-10-14

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Version history (3)
  • version 3 · Final · 2026-10-11 — no change in the headline figures
  • version 2 · Final · 2026-10-11 — no change in the headline figures
  • version 1 · Final · 2026-10-11 — first issue

1 Key messages and climate synopsis

  • National mean temperature of 25.9 °C (+1.7 °C relative to 1991–2020): the 2nd warmest week 39 in the 1979–2026 series.
  • National precipitation of 29.6 mm, 95% of normal: the 27th driest week 39 in the 1979–2026 series.
  • The highest maximum temperature at GHCN stations was 39.8 °C at La Paz (City), B.C.S. on 26 September.
  • The largest 24-hour rainfall at GHCN stations was 59.0 mm at Oaxaca, Oax. on 24 September.
  • 2 station records were broken (stations with at least 20 years of data).
  • Maximum temperature exceeded its 90th percentile on 55% of days (national mean; 10% expected).
  • 1 tropical cyclones passed within 300 km of the country, none making landfall.
  • El Niño conditions of strong intensity in the equatorial Pacific (ONI JJA 2026: +1.8 °C).

Source: NOAA CPC / PSL

Mean temperature
25.9°C
+1.7 °C vs. normal (normal 24.2)
Well above normal
2nd warmest of 48 (1979–2026)
Maximum temperature
32.1°C
+2.6 °C vs. normal (normal 29.5)
Extremely above normal
2nd warmest of 48 (1979–2026)
Minimum temperature
19.7°C
+0.8 °C vs. normal (normal 18.9)
Slightly above normal
3rd warmest of 48 (1979–2026) (tied with 2005, 2024, 2025)
Precipitation
29.6mm
96% of normal (normal 31.0)
Near normal
27th driest of 48 (1979–2026)
Station records
2

Source: NOAA CPC / PSL

2 Global and regional climate drivers

Sea-surface temperature anomaly in the Niño regions (°C)

RegionAnomaly (°C)Change from preceding period (°C)
Niño 1+24.70.1
Niño 33.90.1
Niño 3.43.10.1
Niño 41.10.1

Weekly mean (OISST v2.1)

Source: NOAA CPC

El Niño conditions of strong intensity: the Oceanic Niño Index (ONI) for JJA 2026 was +1.8 °C.

Source: NOAA CPC

Monthly Niño 3.4 anomaly, last 24 months (°C)

Monthly Niño 3.4 anomaly, last 24 months (°C)

Source: NOAA CPC

MJO phase diagram (real-time OMI)

MJO phase diagram (real-time OMI)

Source: NOAA PSL

The Niño 3.4 anomaly was +3.10 °C (+0.10 °C relative to the preceding period).

The MJO was weak or inactive (amplitude below 1 on every day; mean 0.7).

3 Precipitation

National precipitation
29.6mm
96% of normal (normal 31.0)
Near normal
27th driest of 48 (1979–2026)

Source: NOAA CPC / PSL

Accumulated precipitation

Accumulated precipitation

Source: NOAA CPC / PSL

Percent of normal precipitation (1991–2020)

Percent of normal precipitation (1991–2020)

Source: NOAA CPC / PSL

Precipitation by region

RegionTotal (mm)Normal (mm)Difference (%)Category
Northwest15.010.246.6Above normal
North26.913.1106.0Much above normal
Northeast13.629.1−53.3Below normal
North-central12.018.2−34.3Below normal
West-central26.030.0−13.3Near normal
Central19.539.5−50.6Below normal
South66.567.6−1.6Near normal
East54.689.1−38.7Below normal
Yucatán Peninsula48.465.8−26.5Below normal

Source: NOAA CPC / PSL

Stations with the largest precipitation excess

RegionStateStationAltitude (m)Anomaly (%)
NorthCoahuilaSaltillo1790.02329.5
NorthwestBaja California SurLa Paz (City)18.0863.1
NorthDurangoDurango1872.0481.3
North-centralSan Luis PotosíRio Verde983.0271.8
NorthwestBaja California SurCiudad Constitucion48.0254.6
West-centralMichoacánMorelia1913.0204.6
NortheastTamaulipasCiudad Victoria355.0203.9
NorthChihuahuaTemosachi (Obs)1932.044.3

Source: NOAA NCEI

Stations with the largest precipitation deficit

RegionStateStationAltitude (m)Anomaly (%)
NorthwestBaja CaliforniaEjido Nuevo Leon (Obs)11.0−100.0
SouthChiapasTapachula118.0−86.0
CentralTlaxcalaTlaxcala De Xicontecatl (Dge)2230.0−71.3
CentralEstado de MéxicoToluca (Obs)2726.0−58.3
EastVeracruzJalapa1389.0−27.9
EastVeracruzHacienda Ylang Ylang Veracruz16.0−26.8
NortheastTamaulipasTampico25.0−3.5

Source: NOAA NCEI

Largest 24-hour rainfall at stations

StationStateMax 24 h rainfall (mm)Date
OaxacaOaxaca59.02026-09-24
Ciudad VictoriaTamaulipas56.12026-09-23
ColotlanJalisco50.72026-09-23
Chilpancingo Ro.Guerrero47.72026-09-26
La Paz (City)Baja California Sur46.32026-09-23
ZamoraMichoacán45.42026-09-26
MoreliaMichoacán45.42026-09-26
DurangoDurango44.22026-09-25
VillahermosaTabasco40.32026-09-26
Rio VerdeSan Luis Potosí39.82026-09-24

Source: NOAA NCEI

Daily national mean precipitation

Daily national mean precipitation

Source: NOAA CPC / PSL

National accumulated precipitation was 29.6 mm, 95% of the 1991–2020 average (31.0 mm), category “Near normal”. It was the 27th driest week 39 in the 1979–2026 series.

The region with the highest percentage of normal was North (206%) and the lowest was Northeast (47%).

The largest daily grid-cell total was estimated on 27 September in Nayarit (143.8 mm).

Source: NOAA CPC / PSL

4 Temperature

Mean temperature
25.9°C
+1.7 °C vs. normal (normal 24.2)
Well above normal
2nd warmest of 48 (1979–2026)

Source: NOAA CPC / PSL

Mean temperature

Mean temperature

Source: NOAA CPC / PSL

Mean temperature anomaly (1991–2020)

Mean temperature anomaly (1991–2020)

Source: NOAA CPC / PSL

The national mean temperature was 25.9 °C, 1.7 °C above the 1991–2020 average (24.2 °C), category “Well above normal”. It was the 2nd warmest week 39 in the 1979–2026 series.

By region, the largest anomaly was in Northeast (+3.4 °C) and the smallest in East (+0.2 °C).

Source: NOAA CPC / PSL

Maximum temperature
32.1°C
+2.6 °C vs. normal (normal 29.5)
Extremely above normal
2nd warmest of 48 (1979–2026)

Source: NOAA CPC / PSL

Maximum temperature anomaly (1991–2020)

Maximum temperature anomaly (1991–2020)

Source: NOAA CPC / PSL

Lowest and highest monthly mean maximum temperature by region

RegionLowest value (°C)StationHighest value (°C)Station
East30.4Orizaba, Ver.31.3Coatzacoalcos, Ver.

Station monthly means (GHCN-Daily, ≥ 80% of days with data).

Source: NOAA NCEI

Daily national maximum temperature

Daily national maximum temperature

Source: NOAA CPC / PSL

The national maximum temperature was 32.1 °C, 2.6 °C above the 1991–2020 average (29.5 °C), category “Extremely above normal”. It was the 2nd warmest week 39 in the 1979–2026 series.

By region, the largest anomaly was in Northeast (+4.7 °C) and the smallest in East (+1.4 °C).

Source: NOAA CPC / PSL

Minimum temperature
19.7°C
+0.8 °C vs. normal (normal 18.9)
Slightly above normal
3rd warmest of 48 (1979–2026) (tied with 2005, 2024, 2025)

Source: NOAA CPC / PSL

Minimum temperature anomaly (1991–2020)

Minimum temperature anomaly (1991–2020)

Source: NOAA CPC / PSL

Lowest and highest monthly mean minimum temperature by region

RegionLowest value (°C)StationHighest value (°C)Station
Northwest21.2Choix, Sin.25.0La Paz (City), B.C.S.
Yucatán Peninsula24.7Valladolid, Yuc.25.1Progreso, Yuc.

Station monthly means (GHCN-Daily, ≥ 80% of days with data).

Source: NOAA NCEI

Daily national minimum temperature

Daily national minimum temperature

Source: NOAA CPC / PSL

The national minimum temperature was 19.7 °C, 0.8 °C above the 1991–2020 average (18.9 °C), category “Slightly above normal”. It was the 3rd warmest week 39 in the 1979–2026 series (tied with 2005, 2024, 2025).

By region, the largest anomaly was in Northeast (+2.2 °C) and the smallest in East (−1.0 °C).

Source: NOAA CPC / PSL

5 Climate extremes and records

Highest maximum temperature
39.8°C
La Paz (City), B.C.S. · 2026-09-26
Lowest minimum temperature
11.4°C
Comitan, Chis. · 2026-09-22
Highest 24 h rainfall
59.0mm
Oaxaca, Oax. · 2026-09-24

Source: NOAA NCEI

Highest maximum temperature by state

StateStationTemperature (°C)Date
Baja California SurLa Paz (City)39.82026-09-26
ChiapasSn. Cristobal Las Casas31.62026-09-21
CoahuilaSaltillo35.32026-09-24
JaliscoCiudad Guzman34.22026-09-26
OaxacaOaxaca33.02026-09-26
San Luis PotosíRio Verde39.52026-09-21
SinaloaColonia Juan Carras36.82026-09-26
TamaulipasTampico36.42026-09-21
VeracruzCoatzacoalcos35.52026-09-22
YucatánValladolid36.22026-09-23

Source: NOAA NCEI

Lowest minimum temperature by state

StateStationTemperature (°C)Date
Baja California SurLa Paz (City)17.72026-09-27
ChiapasComitan11.42026-09-22
SinaloaChoix14.02026-09-23
TamaulipasTampico18.02026-09-25
VeracruzOrizaba12.12026-09-27
YucatánValladolid23.82026-09-21

Source: NOAA NCEI

Station records broken

StationStateVariableNew valueDatePrevious recordPrevious date
GuadalajaraJaliscoHighest maximum temperature34.02026-09-2732.72023-09-13
OrizabaVeracruzHighest maximum temperature32.42026-09-2531.12020-09-01

Most extreme daily value of the period against the same period in all earlier years of record (at least 20 years; for weeks, the same calendar month).

Source: NOAA NCEI

Climate-extremes indices (national mean)

IndexDescriptionValueNormalDifferenceUnit
TX90pWarm days (Tmax > 90th percentile)55.110.045.1%
TN90pWarm nights (Tmin > 90th percentile)16.310.06.3%
TX10pCool days (Tmax < 10th percentile)1.510.0−8.5%
TN10pCold nights (Tmin < 10th percentile)1.910.0−8.1%
FDFrost days (Tmin < 0 °C)0.00.0−0.0d
SUSummer days (Tmax > 25 °C)6.65.61.0d
TRTropical nights (Tmin > 20 °C)3.63.00.6d
WSDIWarm spell days (≥ 6 days)1.2——d
CSDICold spell days (≥ 6 days)0.0——d
Rx1dayMaximum 1-day precipitation14.915.1−0.1mm
Rx5dayMaximum 5-day precipitation27.028.1−1.1mm
CDDConsecutive dry days (< 1 mm)3.13.7−0.6d
CWDConsecutive wet days (≥ 1 mm)2.52.30.3d

Percentile indices relative to calendar-day percentiles of 1991–2020 (5-day window); counts and maxima averaged over the country's grid cells.

Source: NOAA CPC / PSL

6 Drought

The SPI is computed from monthly totals; see the latest monthly report (SPI).

7 Severe weather and notable events

Tracks of nearby tropical cyclones

Tracks of nearby tropical cyclones
Whole tracks; Saffir–Simpson category from NHC/JTWC. Source: IBTrACS v04 (provisional for recent seasons).

Source: NOAA NCEI

Tropical cyclones within 300 km of the country

NameBasinPeak intensityMaximum wind (km/h)StartEndClosest approach (km)LandfallLandfall intensity
PoloEastern North PacificCategory 5 hurricane2872026-09-172026-09-30115——

Source: NOAA NCEI

Notable events

DatesTypeDetails
2026-04-21 – 2026-10-09DroughtGDACS Orange alert: Drought in The Bahamas, Belize, Costa Rica, Cuba, Dominican Republic, Guatemala, Honduras, Haiti, Mexico, Nicaragua, El Salvador.

GDACS alerts and station rainfall of 150 mm or more in 24 hours (after quality control).

Source: GDACS

Tropical cyclones within 300 km of the country: 1 (Polo).

9 Outlook

Weekly reports do not include a forecast yet; see the outlook in the latest monthly report (NMME seasonal forecast).

11 Glossary, methodology and sources

Anomaly: difference between the observed value and its 1991–2020 normal. Percent of normal: observed total divided by the normal, times 100. Station record: most extreme daily value for the same month in all earlier years of record (at least 20 years).

Temperature: CPC_TEMP (0.5° daily grid); mean temperature is (Tmax + Tmin)/2. Precipitation: CPC. National, regional and state averages are weighted by the area of each grid cell inside each polygon. Normals refer to 1991-2020; ranks compare values rounded to one decimal. Stations: GHCN-Daily (NOAA NCEI); values flagged by its quality control are discarded, as are daily values more than 5 robust standard deviations from the station median and variables whose monthly anomaly differs by more than 3 °C from the gridded analysis. Period means require at least 80% of days with data and station normals at least 20 complete years. This report is generated automatically and does not replace official information from the national meteorological service.

SourceProductLicenseCitation
NOAA CPCONI, Niño-region SST indices (OISST v2.1), NAO and AOPublic domain (NOAA)NOAA Climate Prediction Center climate indices.
NOAA CPC / PSLCPC Global Unified Gauge-Based Analysis of Daily Precipitation, 0.5°Public domain (NOAA)CPC Global Unified Precipitation data provided by NOAA PSL, Boulder, CO, USA.
NOAA CPC / PSLCPC Global Unified Temperature, daily 0.5°Public domain (NOAA)CPC Global Unified Temperature data provided by NOAA PSL, Boulder, CO, USA.
GDACSGlobal Disaster Alert and Coordination System event listSee provider terms—
NOAA NCEIGHCN-DailyPublic domain (NOAA)Menne et al. (2012), J. Atmos. Oceanic Technol., doi:10.1175/JTECH-D-11-00103.1
NOAA NCEIIBTrACS v04r01 tropical-cyclone best tracksPublic domain (NOAA)Knapp et al. (2010), Bull. Amer. Meteor. Soc., doi:10.1175/2009BAMS2755.1
NOAA PSLReal-time OLR MJO Index (ROMI)Public domain (NOAA)Kiladis et al. (2014), Mon. Wea. Rev., doi:10.1175/MWR-D-13-00301.1
geoBoundariesgeoBoundaries gbOpen (Instituto Nacional de Estadística y Geografía (INEGI))Creative Commons Attribution 3.0 Intergovernmental Organisations (CC BY 3.0 IGO)—

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