Dubuque, Iowa climate: Normal weather by month, frost dates and records
Dubuque's normal year runs from 11°F January nights to 82°F July afternoons, with 38.2 inches of precipitation and 43 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 8.4°C, January lows of −12°C, July highs of 28°C, 970 mm of precipitation a year.
- NOAA stationDubuque Regional Airport
- Station IDUSW00094908
- Location42.40°N 90.70°W
- Elevation1,056 ft (322 m)
- Population58,987
On October 14, the normal high in Dubuque is 61°F and the normal low 41°F, and the chance of measurable rain or snow is 28%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Dubuque.
- Jan 27° 11°
- Feb 31° 15°
- Mar 44° 26°
- Apr 58° 37°
- May 69° 49°
- Jun 79° 59°
- Jul 82° 62°
- Aug 80° 60°
- Sep 73° 52°
- Oct 60° 40°
- Nov 45° 28°
- Dec 32° 17°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Dubuque each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 11°F. The most precipitation falls in June (5.19 in), the least in January (1.32 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 27°F | 11°F | 18.8°F | 1.32 | 10.7 | 9 | <1 | 30 | 9 h 20 min |
| February | 31°F | 15°F | 22.9°F | 1.57 | 10.6 | 9 | <1 | 26 | 10 h 30 min |
| March | 44°F | 26°F | 35.2°F | 2.25 | 5.7 | 10 | <1 | 23 | 11 h 50 min |
| April | 58°F | 37°F | 47.4°F | 4.06 | 1.9 | 11 | <1 | 8 | 13 h 20 min |
| May | 69°F | 49°F | 58.8°F | 4.30 | 0.0 | 13 | <1 | 1 | 14 h 30 min |
| June | 79°F | 59°F | 68.5°F | 5.19 | 0.0 | 12 | 2 | <1 | 15 h 20 min |
| July | 82°F | 62°F | 71.7°F | 4.80 | 0.0 | 10 | 3 | <1 | 15 h |
| August | 80°F | 60°F | 69.8°F | 3.95 | 0.0 | 9 | 1 | <1 | 14 h |
| September | 73°F | 52°F | 62.3°F | 3.82 | 0.0 | 9 | <1 | <1 | 12 h 30 min |
| October | 60°F | 40°F | 49.9°F | 2.93 | 0.5 | 9 | <1 | 7 | 11 h 10 min |
| November | 45°F | 28°F | 36.4°F | 2.21 | 2.8 | 8 | <1 | 20 | 9 h 50 min |
| December | 32°F | 17°F | 24.5°F | 1.80 | 10.3 | 9 | <1 | 29 | 9 h 10 min |
| Year (annual) | 56°F | 38°F | 47.2°F | 38.20 | 42.5 | 118 | 6 | 144 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −12°C | −7.3°C | 34 mm | 27 cm |
| February | −1°C | −9°C | −5.1°C | 40 mm | 27 cm |
| March | 7°C | −3°C | 1.8°C | 57 mm | 14 cm |
| April | 14°C | 3°C | 8.6°C | 103 mm | 5 cm |
| May | 21°C | 9°C | 14.9°C | 109 mm | 0 cm |
| June | 26°C | 15°C | 20.3°C | 132 mm | 0 cm |
| July | 28°C | 17°C | 22.1°C | 122 mm | 0 cm |
| August | 26°C | 16°C | 21.0°C | 100 mm | 0 cm |
| September | 23°C | 11°C | 16.8°C | 97 mm | 0 cm |
| October | 16°C | 4°C | 9.9°C | 74 mm | 1 cm |
| November | 7°C | −2°C | 2.4°C | 56 mm | 7 cm |
| December | 0°C | −8°C | −4.2°C | 46 mm | 26 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094908; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Dubuque?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, September has the fewest days with rain (9).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094908.
When is the last frost in Dubuque?
In Dubuque, the last spring frost (32°F) comes after April 28 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 11 in half of years and before September 28 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 281 year in 10 after May 12; 9 in 10 after April 13
- First autumn frost, half of years before
- October 111 year in 10 before September 28; 9 in 10 before October 23
NOAA puts the median frost-free season at 165 days, and the season without a hard freeze (28°F) at 187 days.
A hard freeze (28°F) comes after April 17 in half of springs and before October 21 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Dubuque in zone 5a across its 3 ZIP code areas (5a in 52001, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Dubuque's NOAA station is in zone 5a: the coldest night of a typical year reaches −17°F (30 complete years).
Frost dates for every NOAA station in Iowa · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00094908; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Dubuque ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Dubuque's 3 ZIP code areas are all in zone 5a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Dubuque?
In a normal year in Dubuque, 6 days a year reach 90°F, 144 nights fall to 32°F or colder and 118 days bring measurable precipitation.
- Days at 90°F or more
- 6a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 144a normal year
- Days that stay below freezing
- 61high of 32°F or less
- Days with 0.01 inch of precipitation
- 118a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in Dubuque's official record (kept by the National Weather Service since 1874) is 110°F, on July 14, 1936; the lowest is −32°F, on January 7, 1887.
The wettest calendar year on that record is 1961, with 63.39 in; the snowiest season is 2007–08, with 79.7 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00094908; records: ACIS (NOAA Regional Climate Centers), NWS threaded record DBQthr. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Dubuque, and how clear are its skies?
The summer (June-August) dew point averages 62°F. The muggiest month is July, with an average dew point of 63°F; the driest air comes in January (14°F). March is the windiest month (11.9 mph on average), and August has the most clear or nearly clear hours (72%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 14°F | 78% | 69% | 10.7 mph | 50% | 40% |
| February | 20°F | 74% | 63% | 11.1 mph | 51% | 40% |
| March | 31°F | 65% | 49% | 11.9 mph | 53% | 34% |
| April | 41°F | 64% | 49% | 11.0 mph | 55% | 30% |
| May | 53°F | 69% | 54% | 9.1 mph | 60% | 22% |
| June | 62°F | 73% | 57% | 7.9 mph | 69% | 13% |
| July | 63°F | 76% | 58% | 7.0 mph | 71% | 12% |
| August | 60°F | 77% | 58% | 7.5 mph | 72% | 14% |
| September | 47°F | 71% | 51% | 9.1 mph | 67% | 21% |
| October | 34°F | 72% | 56% | 10.6 mph | 56% | 35% |
| November | 24°F | 78% | 66% | 10.8 mph | 50% | 41% |
| December | 16°F | 80% | 72% | 10.8 mph | 51% | 42% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00094908. Monthly averages of all hours; afternoon humidity at 3 p.m. local standard time; sky as the share of hours NOAA's observations rate clear or few clouds (a dash where NOAA publishes no sky value).
How sunny is Dubuque?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Dubuque, 3.9 kWh per square metre a day. July is the sunniest month (80%) and December the cloudiest (61%). Among the 459 U.S. places of 50,000 or more, that ranks tied 352nd (with 32 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 65% | 1.8 |
| February | 71% | 2.8 |
| March | 69% | 3.7 |
| April | 69% | 4.7 |
| May | 71% | 5.6 |
| June | 75% | 6.1 |
| July | 80% | 6.3 |
| August | 79% | 5.4 |
| September | 79% | 4.4 |
| October | 70% | 2.9 |
| November | 68% | 2.0 |
| December | 61% | 1.4 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Dubuque need?
A normal year in Dubuque brings 7,084 heating degree days, 32% more than the median U.S. place (5,373), and 638 cooling degree days, 30% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,745 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,432 | 0 |
| February | 1,177 | 0 |
| March | 924 | 1 |
| April | 529 | 3 |
| May | 229 | 38 |
| June | 37 | 143 |
| July | 8 | 217 |
| August | 18 | 166 |
| September | 142 | 63 |
| October | 475 | 7 |
| November | 857 | 0 |
| December | 1,255 | 0 |
| Year (annual) | 7,084 | 638 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00094908. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
Has Dubuque been warmer than normal lately?
2024 averaged 51.2°F, 4.0°F above the 1991-2020 normal of 47.2°F. 3 of the 4 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 49.0°F | +1.8°F | 29.85 | 42.9 |
| 2022 | 47.0°F | −0.2°F | 31.47 | 36.2 |
| 2023 | 50.0°F | +2.8°F | 32.27 | 50.5 |
| 2024 | 51.2°F | +4.0°F | 40.52 | 40.8 |
Over 169 complete years from 1851 to 2025, the station's annual mean temperature rose at a fitted 1.5°F per century (+0.08°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00094908; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Dubuque's climate compare?
Dubuque is warmer than 51 of the other 131 places with their own NOAA record in Iowa, and wetter than 99. Across the 7,247 U.S. stations with normals, its annual mean of 47.2°F is warmer than 29%.
In the Köppen classification computed from these normals, Dubuque is Dfa: continental, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Dubuque share this climate record?
12 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Asbury, IA6,051 people · 9 mi NW
- Peosta, IA2,195 people · 8 mi NW
- East Dubuque, IL1,457 people · 7 mi NE
- Dickeyville, WI1,087 people · 17 mi N
- Potosi, WI656 people · 20 mi N
- Kieler, WI334 people · 14 mi N
- Sandy Hook, WI261 people · 11 mi NE
- Menominee, IL206 people · 10 mi NE
- Bernard, IA117 people · 9 mi SW
- Centralia, IA117 people · 9 mi NW
- Zwingle, IA86 people · 7 mi S
- Graf, IA76 people · 11 mi NW
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
What do Dubuque's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Dubuque. This page uses Dubuque Regional Airport; the other differs by site and elevation:
| Station | From this station | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Dubuque Lock and Dam 11 USC00132364 | 10 mi N | 620 ft | 48.4°F | 10°F | 85°F | 38.8 | 36 | April 19 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Dubuque's climate
What is the coldest month in Dubuque?
January, with a normal high of 27°F and a normal low of 11°F. The warmest is July (82°F by day, 62°F at night).
Does it snow in Dubuque?
Yes: 43 inches in a normal year, falling on 29 days with 0.1 inch or more, the most in January (10.7 inches).
What is the rainiest month in Dubuque?
June, with 5.19 in of precipitation in a normal year; the driest is January with 1.32 in.
What plant hardiness zone is Dubuque in?
The USDA's 2023 map puts Dubuque in zone 5a across its 3 ZIP code areas (5a in 52001, the largest). By the same method at Dubuque's NOAA station, the coldest night of a typical year reaches −17°F (30 years, 1991-2020): zone 5a.
How late can frost come in Dubuque?
In half of years the last 32°F night comes after April 28; in one year in ten it comes after May 12. Waiting until May 12 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Dubuque in OctoberThis month day by day, its records and recent years
- Iowa climateThe statewide normals and every place in the state
- Galena, IL16 miles from this station, 47.0°F a year
- Bellevue, IA17 miles from this station, 48.7°F a year
- Cascade, IA17 miles from this station, 47.9°F a year
- Maquoketa, IA22 miles from this station, 47.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made