Delaware Climate – July 2026 Update
Top 5 Cities: Wilmington, Dover, Newark, Middletown, and Smyrna
Summary
Delaware experienced its 9th wettest July on record alongside unprecedented local fire activity, while the broader planet logged its 3rd warmest month in recorded history. Extreme heat alerts and severe midsummer downpours dominated the state, making Delaware the warmest state relative to baseline in the Northeast region. Warm conditions are expected to persist across the area into late summer and early autumn.
This month in numbers
Delaware recorded an average temperature of 26°C during the month, standing 1.8°C above the 1961-1990 baseline to mark the 13th warmest July in 77 years of data. Maximum temperatures reached an average of 31.67°C, also ranking 13th highest. Total precipitation reached 169.16 mm, an excess of 70.7 mm above average that secured the 9th wettest July on record. Globally, land temperatures reached 15.8°C (+1.6°C anomaly), making it the 3rd warmest July in 87 years of global record-keeping.
What changed
The three-month period from May to July averaged 22.5°C (+1.7°C anomaly), ranking as Delaware's 10th warmest May-July on record, while daytime highs averaged 28.45°C, the 7th highest on record. Within the NOAA Northeast US climate region group (US Northeast), Delaware registered the highest temperature departure, running 0.79°C warmer than the regional average. Across the entire United States, average temperatures settled at 23.01°C (+1.5°C anomaly) for the month, while global land temperatures over the May to July window ranked as the 2nd warmest on record.
What’s driving change?
Recent warmth and heavy rain in Delaware were shaped by larger atmospheric patterns over North America. Heat trapped under stagnant high pressure raised humidity levels, while local effects in built-up areas kept overnight temperatures elevated. Because waters, continental air masses heated rapidly. Meanwhile, allowed weather fronts to stall, triggering convective storms that delivered high rainfall totals. All of Delaware's 3 wildfires this year have happened in the past month, tracked on our live map at Extreme Weather tracker.
Looking ahead
Official long-range outlooks indicate that temperatures are likely to remain above normal across Delaware through late summer and into autumn.
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 – Delaware
Köppen Cfa · TemperateDelaware has a temperate climate (Köppen Cfa: Humid subtropical), with distinct warm summers and cool-to-cold winters. July is typically the warmest month, averaging 26.1°C, while January is the coldest at 2.2°C. Annual precipitation averages around 1147mm, spread fairly evenly across the year.
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 – Delaware
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 – Delaware
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 – Delaware
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Monthly Temperature – Delaware
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 – Delaware
NOAA National Centers for Environmental Information (frost: World Bank CCKP; snow: GPCC (DWD)) - Anomalies vs 1901-2000 mean
Shifting Seasons
Warm / cold seasonsKöppen Cfa · TemperateHow spring and autumn have shifted in Delaware. 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 23.6°C peak-to-peak across the year - a classic four-seasons rhythm.
Baseline vs recent monthly temperature climatology. Biggest warming: Feb (+3.3°C).
Data: NOAA National Centers for Environmental Information (temperature/precipitation; frost: World Bank CCKP; snow: GPCC (DWD)).
Emissions & Energy
Explore
Explore Climate Data
Data Sources
Data Sources for Delaware
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 Delaware changing?
Delaware 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 Delaware?
Delaware has a temperate climate (Köppen Cfa: Humid subtropical), with distinct warm summers and cool-to-cold winters. July is typically the warmest month, averaging 26.1°C, while January is the coldest at 2.2°C. Annual precipitation averages around 1147mm, spread fairly evenly across the year.
Where does the climate data for Delaware come from?
Climate data for Delaware 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 Delaware climate data cover?
The Delaware climate profile covers Wilmington, Dover, Newark, Middletown and surrounding areas. Delaware climate data from NOAA Climate at a Glance
How often is the Delaware climate update refreshed?
The Delaware 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 Delaware 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 Delaware 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.