US West Climate – July 2026 Update
Top States: California and Nevada
Generating fresh US West climate update… This refreshes monthly when new data lands. Reload in a minute to see the latest analysis.
At a Glance
Temperature – Average
Climate Map – USUnited States
Source: NOAA Climate at a Glance — US states & climate regions (tavg, pcp), plus GPCC (Snow, water-equivalent). Anomalies are vs the 1961–1990 baseline. See methodology.
Long-Term Trends
Combined Timeline – US West
Right axis: everything else standardized to standard deviations (σ) from its own average, since mm/hours/days aren't directly comparable to °C or to each other.
NOAA Climate at a Glance - regional tavg / pcp
Heatwave Days – US West
Warm Spell Duration Index (WSDI) - the WMO/ETCCDI heatwave measure: days in a 6+ day run above the local 90th-percentile temperature for that time of year.
Data: World Bank Climate Change Knowledge Portal (ERA5-derived), aggregated by 4BYO across member states. Refreshed roughly 1-2x/year, ~7-8 months behind present.
Hottest & Coolest in US West this Month
1-month anomaly vs 1961–1990 across the 2 members we cover. Click a name to open its profile.
Warmest
- 1.🇺🇸Nevada+2.30°C
- 2.☀️California+1.53°C
Coolest
- 1.☀️California+1.53°C
- 2.🇺🇸Nevada+2.30°C
Member States
Year-on-Year Trends
The 4byo Climate Helix – US West
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
Monthly Temperature – US West
Background lines show the last 40 years (plus the record year and its opposite, wherever they fall).
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
Records – US West
NOAA Climate at a Glance - regional tavg / pcp - Anomalies vs 1901-2000 mean
Shifting Seasons
Warm / cold seasonsHow spring and autumn have shifted in US West. Spring is defined as the date monthly temperatures first rise above the long-term annual mean (12.3°C, from 1950–1979); autumn is the date they fall back below it. Temperature swings 20.4°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Jun (+2.0°C).
NOAA Climate at a Glance — regional tavg. Baseline: first 30 yrs on record. Recent: last 10 yrs on record.
Climate Systems
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Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for US West
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.
US 9-region temperature and precipitation series (1895–present).
US state-level CO₂ emissions and electricity generation mix by fuel source. Energy Information Administration.
Frost Days and Heatwave Days (Warm Spell Duration Index), ERA5-derived. World Bank Climate Change Knowledge Portal.
Monthly snow water-equivalent, Global Precipitation Climatology Centre (DWD).
FAQs
FAQs
How is the climate in US West changing?
US West 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 West come from?
Climate data for US West 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 West climate data cover?
The US West climate profile covers California, Nevada and surrounding areas. NOAA West - CA, NV
How often is the US West climate update refreshed?
The US West 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.
What counts as a Heatwave Day on the US West climate page?
Heatwave Days use the Warm Spell Duration Index (WSDI) - the WMO/ETCCDI-standard heatwave measure: days that are part of a run of 6 or more consecutive days above the local 90th-percentile temperature for that calendar day. The 90th-percentile threshold varies by time of year (a hot day in January is judged differently to one in July) but is fixed to the 1961-1990 baseline for every year shown - it does not shift as the climate warms, which is why Heatwave Days trend upward over time.
Does the US West climate page include frost and snow data?
Yes. Frost Days (days with a minimum temperature below 0°C, World Bank CCKP) and snow water-equivalent (GPCC) are shown alongside temperature and precipitation, each measured against the 1961-1990 baseline where a like-for-like historical comparison is available.