Idaho Climate – July 2026 Update
Top 5 Cities: Boise, Meridian, Nampa, Idaho Falls, and Pocatello
Summary
Idaho experienced its 3rd warmest July on record as intense heat blanketed the state, pushing average temperatures to 21.44°C, a full 3.1°C above the long-term baseline. The summer heat wave brought persistent triple-digit temperatures and high air quality advisories across the Treasure Valley as wildfire smoke drifted across the Pacific Northwest. The extreme month capped off a May to July season that ranked as the state's 4th warmest in 77 years of recorded climate history. Globally, the climate pattern is being influenced by a moderate El Niño forecast to peak at Very Strong in Sep-Nov, with elevated temperatures expected to persist over the coming months.
This month in numbers
July 2026 stood out as the 3rd warmest on record for Idaho, averaging 21.44°C with an anomaly of +3.1°C against the 1961-1990 baseline. Daytime maximum temperatures averaged 30.28°C, which was 3.3°C above baseline and the 6th highest recorded for the month. Rain was scarce, with total precipitation reaching just 12.95 mm, down 10.4 mm from normal. Taking a broader view, the 3-month period spanning May to July averaged 15.9°C (+2°C above baseline), ranking as the 4th warmest such season on record. Average maximum temperatures over those 3 months hit 24.24°C, also ranking 4th highest. Worldwide, global land temperatures reached 15.8°C (+1.6°C anomaly), marking the 3rd warmest July on record globally.
What changed
Idaho's heat outpaced much of the country, with its monthly anomaly running more than double the US national average of +1.5°C. Within the NOAA Northwest US climate region, Idaho stood as the warmest state over the month, leading neighbours Oregon and Washington at US Northwest. Over the full past 12 months, Idaho recorded a rolling temperature anomaly of +2.79°C, placing it 10th highest out of 232 countries and regions globally. Notably, 7 of the top 10 highest 12-month anomalies worldwide belong to US states, highlighting a striking geographic cluster of sustained heat across the American West.
What’s driving change?
The intense summer heat was largely anchored by persistent that trapped high pressure and hot air across the region. As dry conditions drained moisture from the landscape, further exacerbated surface heating by eliminating evaporative cooling. Regional fire activity also escalated, and all of Idaho's 1 wildfire tracked this year occurred in the past month, as shown on our live tracker at Extreme Weather tracker. On a global scale, ENSO is currently in a moderate El Niño phase, which historically brings a modest, loosely correlated tendency toward milder and drier winter conditions to the Pacific Northwest, with live monitoring available at ENSO.
Looking ahead
Seasonal forecasts indicate that above-average temperatures are likely to persist across Idaho through late summer and into autumn, while ocean models project a 93% probability that El Niño will reach Very Strong intensity between September and November.
Generated by Gemini from climate data and web sources
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.
Typical Climate – Idaho
Köppen Dsb · ContinentalIdaho has a continental climate (Köppen Dsb: Continental - dry, warm summer), with both a warm/cold cycle and a wet/dry cycle through the year. July is typically the warmest month, averaging 20.0°C, while January is the coldest at -3.9°C. Annual precipitation averages around 589mm, concentrated mostly in the wet season.
Monthly climate normals (2016–2025) - bar colour and height show average temperature, the shaded area shows average monthly rain, with snow (water-equivalent) shown separately.
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Long-Term Trends
Combined Timeline – Idaho
Precipitation, Sunshine, Frost and Snow are converted to standard deviations from their own average so they can share an axis with Temperature.
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Heatwave Days – Idaho
Warm Spell Duration Index (WSDI) - 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). Refreshed roughly 1-2x/year, ~7-8 months behind present.
Year-on-Year Trends
The 4byo Climate Helix – Idaho
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Monthly Temperature – Idaho
Background lines show the last 40 years (plus the record year and its opposite, wherever they fall).
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Records – Idaho
NOAA National Centers for Environmental Information (frost: World Bank CCKP; snow: GPCC (DWD)) - Anomalies vs 1901-2000 mean
Shifting Seasons
Warm/cold + wet/dryKöppen Dsb · ContinentalIdaho has both a clear warm/cold cycle (±11.9°C) and a wet/dry cycle (5× wet:dry ratio). Both sides of the annual rhythm are shown below.
Monthly precipitation climatology. A “wet month” exceeds the baseline monthly mean (dashed gold line). Biggest month-to-month shift: Jan (-22 mm, -25%).
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Climate Systems
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Emissions & Energy
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Data Sources
Data Sources for Idaho
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.
Statewide monthly temperature and precipitation (nClimDiv).
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 Idaho changing?
Idaho 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.
What is the climate like in Idaho?
Idaho has a continental climate (Köppen Dsb: Continental - dry, warm summer), with both a warm/cold cycle and a wet/dry cycle through the year. July is typically the warmest month, averaging 20.0°C, while January is the coldest at -3.9°C. Annual precipitation averages around 589mm, concentrated mostly in the wet season.
Where does the climate data for Idaho come from?
Climate data for Idaho comes from NOAA Climate at a Glance (temperature and precipitation), 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 Idaho climate data cover?
The Idaho climate profile covers Boise, Meridian, Nampa, Idaho Falls and surrounding areas. Idaho climate data from NOAA Climate at a Glance
How often is the Idaho climate update refreshed?
The Idaho 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 Idaho 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 Idaho 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.