Hartford, Connecticut climate: Normal weather by month, frost dates and records
Hartford's normal year runs from 19°F January nights to 85°F July afternoons, with 47.0 inches of precipitation and 52 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.6°C, January lows of −7°C, July highs of 30°C, 1,195 mm of precipitation a year.
- NOAA stationHartford-Bradley International Airport
- Station IDUSW00014740
- Location41.94°N 72.68°W
- Elevation190 ft (58 m)
- From the center12 miles
- Population122,129
On October 14, the normal high in Hartford is 64°F and the normal low 43°F, and the chance of measurable rain or snow is 34%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Hartford.
- Jan 35° 19°
- Feb 39° 21°
- Mar 47° 28°
- Apr 61° 38°
- May 72° 48°
- Jun 80° 58°
- Jul 85° 63°
- Aug 83° 62°
- Sep 76° 54°
- Oct 64° 42°
- Nov 52° 33°
- Dec 41° 25°
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 Hartford each month?
July is the warmest month, with normal highs of 85°F; January the coldest, with normal lows of 19°F. The most precipitation falls in October (4.52 in), the least in February (3.13 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 | 35°F | 19°F | 27.1°F | 3.28 | 14.2 | 11 | <1 | 27 | 9 h 30 min |
| February | 39°F | 21°F | 29.6°F | 3.13 | 14.8 | 11 | <1 | 25 | 10 h 30 min |
| March | 47°F | 28°F | 37.8°F | 3.81 | 9.4 | 11 | <1 | 21 | 11 h 50 min |
| April | 61°F | 38°F | 49.5°F | 3.88 | 1.1 | 12 | <1 | 7 | 13 h 20 min |
| May | 72°F | 48°F | 60.0°F | 3.79 | 0.0 | 12 | 1 | <1 | 14 h 30 min |
| June | 80°F | 58°F | 68.9°F | 4.28 | 0.0 | 12 | 4 | <1 | 15 h 10 min |
| July | 85°F | 63°F | 74.3°F | 4.17 | 0.0 | 11 | 8 | <1 | 15 h |
| August | 83°F | 62°F | 72.5°F | 4.21 | 0.0 | 10 | 5 | <1 | 13 h 50 min |
| September | 76°F | 54°F | 64.8°F | 4.39 | 0.0 | 9 | 1 | <1 | 12 h 30 min |
| October | 64°F | 42°F | 53.0°F | 4.52 | 0.7 | 11 | <1 | 4 | 11 h 10 min |
| November | 52°F | 33°F | 42.3°F | 3.51 | 1.4 | 10 | <1 | 15 | 9 h 50 min |
| December | 41°F | 25°F | 32.6°F | 4.08 | 10.1 | 12 | <1 | 25 | 9 h 10 min |
| Year (annual) | 61°F | 41°F | 51.0°F | 47.05 | 51.7 | 130 | 20 | 126 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 2°C | −7°C | −2.7°C | 83 mm | 36 cm |
| February | 4°C | −6°C | −1.3°C | 80 mm | 38 cm |
| March | 8°C | −2°C | 3.2°C | 97 mm | 24 cm |
| April | 16°C | 4°C | 9.7°C | 99 mm | 3 cm |
| May | 22°C | 9°C | 15.6°C | 96 mm | 0 cm |
| June | 27°C | 14°C | 20.5°C | 109 mm | 0 cm |
| July | 30°C | 17°C | 23.5°C | 106 mm | 0 cm |
| August | 29°C | 17°C | 22.5°C | 107 mm | 0 cm |
| September | 24°C | 12°C | 18.2°C | 112 mm | 0 cm |
| October | 18°C | 6°C | 11.7°C | 115 mm | 2 cm |
| November | 11°C | 1°C | 5.7°C | 89 mm | 4 cm |
| December | 5°C | −4°C | 0.3°C | 104 mm | 26 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014740; 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 Hartford?
Normal highs sit between 65°F and 85°F in May, June, 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 USW00014740.
When is the last frost in Hartford?
In Hartford, the last spring frost (32°F) comes after April 21 in half of years and after May 6 in one year in ten; the first autumn frost comes before October 16 in half of years and before October 3 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 211 year in 10 after May 6; 9 in 10 after April 8
- First autumn frost, half of years before
- October 161 year in 10 before October 3; 9 in 10 before November 2
NOAA puts the median frost-free season at 177 days, and the season without a hard freeze (28°F) at 204 days.
A hard freeze (28°F) comes after April 7 in half of springs and before October 29 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Hartford in zone 6b across its 6 ZIP code areas (6b in 06106, the largest). By the map's own method, the average of each year's coldest night over 1991-2020, Hartford's NOAA station is in zone 6b: the coldest night of a typical year reaches −3°F (30 complete years).
Frost dates for every NOAA station in Connecticut · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00014740; 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 Hartford ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Hartford's 6 ZIP code areas are all in zone 6b. 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 Hartford?
In a normal year in Hartford, 20 days a year reach 90°F, 126 nights fall to 32°F or colder and 130 days bring measurable precipitation.
- Days at 90°F or more
- 20a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 126a normal year
- Days that stay below freezing
- 28high of 32°F or less
- Days with 0.01 inch of precipitation
- 130a normal year
- Days with 1 inch of snow or more
- 13a normal year
The highest temperature in Hartford's official record (kept by the National Weather Service since 1905) is 103°F, on July 22, 2011; the lowest is −26°F, on January 22, 1961.
The wettest calendar year on that record is 2011, with 69.23 in; the snowiest season is 1995–96, with 114.6 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USW00014740; records: ACIS (NOAA Regional Climate Centers), NWS threaded record BDLthr. Records use complete months only; a month missing more than three days is left out.
How humid and windy is Hartford, and how clear are its skies?
The summer (June-August) dew point averages 61°F. The muggiest month is July, with an average dew point of 62°F; the driest air comes in January (16°F). March is the windiest month (9.1 mph on average), and August has the most clear or nearly clear hours (46%).
| Month | Dew point | Humidity | Afternoon humidity | Wind | Clear or few clouds | Overcast |
|---|---|---|---|---|---|---|
| January | 16°F | 61% | 48% | 8.2 mph | 38% | 33% |
| February | 20°F | 60% | 47% | 9.1 mph | 35% | 38% |
| March | 28°F | 56% | 39% | 9.1 mph | 37% | 37% |
| April | 39°F | 56% | 38% | 8.5 mph | 36% | 34% |
| May | 52°F | 66% | 46% | 7.6 mph | 31% | 34% |
| June | 61°F | 67% | 47% | 6.8 mph | 39% | 21% |
| July | 62°F | 69% | 49% | 6.2 mph | 40% | 22% |
| August | 59°F | 70% | 48% | 6.3 mph | 46% | 19% |
| September | 50°F | 74% | 52% | 6.6 mph | 45% | 27% |
| October | 37°F | 67% | 49% | 7.7 mph | 41% | 33% |
| November | 28°F | 67% | 54% | 7.7 mph | 35% | 36% |
| December | 20°F | 66% | 54% | 8.2 mph | 36% | 36% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00014740. 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 Hartford?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Hartford, 3.9 kWh per square metre a day. July is the sunniest month (79%) and December the cloudiest (67%). 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 | 70% | 1.9 |
| February | 70% | 2.7 |
| March | 69% | 3.7 |
| April | 71% | 4.9 |
| May | 70% | 5.5 |
| June | 74% | 5.9 |
| July | 79% | 6.0 |
| August | 79% | 5.3 |
| September | 78% | 4.4 |
| October | 71% | 2.9 |
| November | 72% | 2.1 |
| December | 67% | 1.5 |
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 Hartford need?
A normal year in Hartford brings 5,883 heating degree days, 10% more than the median U.S. place (5,373), and 819 cooling degree days, 10% 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 3,069 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,176 | 0 |
| February | 991 | 0 |
| March | 845 | 0 |
| April | 473 | 7 |
| May | 193 | 40 |
| June | 35 | 150 |
| July | 2 | 290 |
| August | 6 | 238 |
| September | 93 | 86 |
| October | 382 | 8 |
| November | 683 | 0 |
| December | 1,004 | 0 |
| Year (annual) | 5,883 | 819 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014740. 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 Hartford been warmer than normal lately?
2025 averaged 51.5°F, 0.5°F above the 1991-2020 normal of 51.0°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 52.7°F | +1.7°F | 54.94 | 30.1 |
| 2022 | 52.7°F | +1.7°F | 47.91 | 34.4 |
| 2023 | 53.6°F | +2.6°F | 64.91 | 17.1 |
| 2024 | 55.0°F | +4.0°F | 45.81 | 29.4 |
| 2025 | 51.5°F | +0.5°F | 46.63 | 27.5 |
Over 74 complete years from 1943 to 2023, the station's annual mean temperature rose at a fitted 4.5°F per century (+0.25°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: observed years: ACIS, station USW00014740; trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does Hartford's climate compare?
Hartford is warmer than 7 of the other 12 places with their own NOAA record in Connecticut, and wetter than 6. Across the 7,247 U.S. stations with normals, its annual mean of 51.0°F is warmer than 45%.
In the Köppen classification computed from these normals, Hartford 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 Hartford share this climate record?
13 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.
- Springfield, MAalso near: Westfield (10 mi, 49.4°F a year); Belchertown (15 mi, 47.7°F a year)154,888 people · 14 mi NE
- East Hartford, CTalso near: Burlington (17 mi, 50.0°F a year); Storrs (20 mi, 49.6°F a year)51,127 people · 13 mi S
- Manchester, CT59,948 people · 14 mi SE
- West Springfield, MA29,028 people · 13 mi N
- Agawam, MA28,749 people · 9 mi N
- Longmeadow, MA15,712 people · 10 mi NE
- Windsor Locks, CT12,643 people · 2 mi SE
- Southwood Acres, CT8,154 people · 6 mi E
- Glastonbury Center, CT7,860 people · 17 mi S
- Simsbury Center, CT6,326 people · 8 mi SW
- Broad Brook, CT3,550 people · 8 mi E
- Blue Hills, CT1,989 people · 9 mi S
- Tariffville, CT1,607 people · 5 mi SW
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 Hartford's other NOAA stations record?
One more NOAA station keeps 1991-2020 normals in or near Hartford. This page uses Hartford-Bradley International Airport; the other differs by site and elevation:
| Station | From the center | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| Hartford Brainard Field USW00014752 | 3 mi SE | 19 ft | 52.0°F | 20°F | 85°F | 42.8 | – | April 17 |
Source: NOAA NCEI 1991-2020 normals for each station. Last frost: the median last spring date of 32°F.
Questions about Hartford's climate
What is the coldest month in Hartford?
January, with a normal high of 35°F and a normal low of 19°F. The warmest is July (85°F by day, 63°F at night).
Does it snow in Hartford?
Yes: 52 inches in a normal year, falling on 22 days with 0.1 inch or more, the most in February (14.8 inches).
What is the rainiest month in Hartford?
October, with 4.52 in of precipitation in a normal year; the driest is February with 3.13 in.
What plant hardiness zone is Hartford in?
The USDA's 2023 map puts Hartford in zone 6b across its 6 ZIP code areas (6b in 06106, the largest). By the same method at Hartford's NOAA station, the coldest night of a typical year reaches −3°F (30 years, 1991-2020): zone 6b.
How late can frost come in Hartford?
In half of years the last 32°F night comes after April 21; in one year in ten it comes after May 6. Waiting until May 6 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Hartford in OctoberThis month day by day, its records and recent years
- Connecticut climateThe statewide normals and every place in the state
- Barkhamsted, CT14 miles from this station, 48.5°F a year
- Westfield, MA16 miles from this station, 49.4°F a year
- Burlington, CT16 miles from this station, 50.0°F a year
- Bakersville, CT18 miles from this station, 47.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made