US Northwest Climate – March 2026 Update
Top States: Washington, Oregon, and Idaho
This month in numbers
The US Northwest experienced a significantly warm month, with a 1-month temperature anomaly of +3.41°C above the 1961–1990 average. The 3-month anomaly stands at +3.32°C, and the 12-month rolling anomaly is +2.23°C. This places the US Northwest among the warmest regions globally, as 10 of the top 10 warmest regions in the latest month were US states.
Hottest & coolest US states
Idaho was notably warm this month, recording an anomaly of +4.79°C. Oregon also experienced unusually high temperatures at +3.99°C. Washington followed with a +1.46°C anomaly. climate page climate page climate page Alaska, however, stood out as the coolest US state, with a 1-month anomaly of -5.93°C.
What's driving change?
The current ENSO state is Neutral, with an anomaly of +0.11°C vs 1991–2020. The dominant probability for the next 1–2 seasons is a transition to El Niño, with a 61% chance for May-Jul and 79% for Jun-Aug. ENSO tracker This neutral phase, following a warm winter, has contributed to persistent warmth across the region. The US Northwest, along with other western US states, experienced its second warmest winter on record (December 2025–February 2026). This warm winter led to a significantly reduced snowpack, with many basins experiencing an early peak and rapid melt-out. This , where dry soils cannot cool through evaporation, further exacerbates warming and contributes to drought conditions. In April, above-average precipitation fell across parts of the West and Northwest, but despite this, drought is expected to persist and potentially expand in the Northwest in May.
Looking ahead
Above-average temperatures are forecast across much of the western contiguous US for May, with the highest probabilities over the Northwest, while below-average precipitation is favored across much of the Northwest.
Generated by Gemini from climate data and web sources
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.
Temperature – Average
US Northwest – Monthly Temperature – All Years
Each line represents one year of monthly temperature in °C.
NOAA Climate at a Glance — regional tavg / pcp (monthly absolutes).
Shifting Seasons
Warm / cold seasonsHow spring and autumn have shifted in US Northwest. Spring is defined as the date monthly temperatures first rise above the long-term annual mean (7.3°C, from 1950–1979); autumn is the date they fall back below it. Temperature swings 21.0°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Aug (+1.9°C).
NOAA Climate at a Glance — regional tavg.
Rainfall & Rain Days – Totals
Member States (3)
Hottest & Coolest in US Northwest this Month
1-month anomaly vs 1961–1990 across the 3 members we cover. Click a name to open its profile.
Warmest
- 1.🇺🇸Oregon+1.76°C
- 2.🇺🇸Washington+1.61°C
- 3.🇺🇸Idaho+0.88°C
Coolest
- 1.🇺🇸Idaho+0.88°C
- 2.🇺🇸Washington+1.61°C
- 3.🇺🇸Oregon+1.76°C
Data Sources
- NOAA Climate at a Glance — Regional time series · NOAA code 108 · Open at NOAA
- Two-baseline model — comparison baseline 1961–1990; native baseline 1901–2000. Methodology →
Data Sources
Data Sources for US Northwest
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 Northwest changing?
US Northwest 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 trend rate is shown as °C per decade in the headline panel; you can also see the warmest and coolest years on file.
Where does the climate data for US Northwest come from?
Climate data for US Northwest 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 Northwest climate data cover?
The US Northwest climate profile covers Washington, Oregon, Idaho and surrounding areas. NOAA Northwest - ID, OR, WA
How often is the US Northwest climate update refreshed?
The US Northwest 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.