US Southwest Climate – May 2026 Update
Top States: Arizona, Colorado, New Mexico, and Utah
This month in numbers
The US Southwest experienced a significantly warm May 2026, with temperatures averaging +1.42°C above the 1961–1990 average. This continues a trend of elevated temperatures, as the 3-month anomaly stands at +3.66°C and the 12-month rolling anomaly is +2.98°C. Globally, May 2026 ranked as the second-warmest May on record, trailing only 2024.
Hottest & coolest US states
Within the US Southwest, Utah (US Utah) led the warming trend in May with an anomaly of +1.82°C, followed closely by Arizona (US Arizona) at +1.62°C. New Mexico (US New Mexico) also saw significantly above-average temperatures at +1.41°C. Colorado (US Colorado) was comparatively cooler within the region, with an anomaly of +0.88°C. Arizona, New Mexico, and Colorado each recorded their warmest spring on record.
What's driving change?
The current climate pattern is heavily influenced by a rapidly developing El Niño. The NOAA CPC indicates a Neutral ENSO state for MAM 2026 with an anomaly of +0.48°C, but forecasts show a 97% probability of El Niño for May-Jul, rising to 99% for Jun-Aug and Jul-Sep, and 100% for Aug-Oct and Sep-Nov. This strong El Niño is expected to bring increased precipitation and potential flood risk to the Southwestern United States, though drought conditions persisted and expanded across portions of the Southwest in May. The region is also experiencing the effects of , as much of the western interior, Rockies, and Plains remained in drought, with some areas seeing intensification.
Looking ahead
The strong El Niño is expected to continue developing, with a high likelihood of a historically significant event by autumn or early winter, which typically brings a wetter winter to the Southwest.
Generated by Gemini from climate data and web sources
At a Glance
Temperature – Average
Climate Map – USA
Source: NOAA Climate at a Glance — US states & climate regions (tavg, pcp). Anomalies are vs the 1961–1990 baseline (temperature) or 1991–2020 (rainfall). See methodology.
Hottest & Coolest in US Southwest this Month
1-month anomaly vs 1961–1990 across the 4 members we cover. Click a name to open its profile.
Warmest
- 1.🇺🇸Utah+1.82°C
- 2.🇺🇸Arizona+1.62°C
- 3.🇺🇸New Mexico+1.41°C
- 4.🇺🇸Colorado+0.88°C
Coolest
- 1.🇺🇸Colorado+0.88°C
- 2.🇺🇸New Mexico+1.41°C
- 3.🇺🇸Arizona+1.62°C
- 4.🇺🇸Utah+1.82°C
Member States
Year-on-Year Trends
The 4byo Climate Helix – US Southwest
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
US Southwest – Monthly Temperature – All Years
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
Records – US Southwest
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
Shifting Seasons
Warm / cold seasonsHow spring and autumn have shifted in US Southwest. Spring is defined as the date monthly temperatures first rise above the long-term annual mean (10.8°C, from 1950–1979); autumn is the date they fall back below it. Temperature swings 23.3°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Dec (+2.0°C).
NOAA Climate at a Glance — regional tavg. Baseline: first 30 yrs on record. Recent: last 10 yrs on record.
Rainfall & Rain Days – Totals
Climate Systems
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Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for US Southwest
Every figure on this page is sourced from official, openly published climate datasets. Anomalies are calculated against the 1961–1990 baseline (temperature) and 1991–2020 (rainfall, sunshine, frost) - see the Methodology & Sources page for the complete dataset list and update calendar.
FAQs
FAQs
How is the climate in US Southwest changing?
US Southwest is warming in line with the rest of the world. The page above shows the latest monthly temperature anomaly versus the 1961-1990 baseline, the long-term annual trend, and the region's rank in the historical record. The headline panel also shows the long-term trend rate per decade and the warmest and coolest years on file.
Where does the climate data for US Southwest come from?
Climate data for US Southwest comes from authoritative climate datasets including national meteorological services and peer-reviewed reanalyses, refreshed every month, when the upstream temperature and rainfall data are refreshed.
What is the climate baseline used on this page?
Anomalies on this page are calculated against the 1961-1990 climatological baseline, which is the standard reference period used by the Met Office, NOAA, IPCC and most national climate services. Some panels also show the source-native 1901-2000 (NOAA) or 1991-2020 (WMO) baselines for verification. See Methodology & Sources for the full reference.
Which areas does the US Southwest climate data cover?
The US Southwest climate profile covers Arizona, Colorado, New Mexico, Utah and surrounding areas. NOAA Southwest - AZ, CO, NM, UT
How often is the US Southwest climate update refreshed?
The US Southwest climate update is refreshed monthly, typically a few days after the previous month closes and the upstream provider (Met Office HadUK-Grid, NOAA Climate at a Glance, Copernicus ERA5 or the Global Carbon Project) publishes its update. See the Climate Rankings for cross-region comparisons.