Hartford, Maine climate: Climate normals at a NOAA weather station
Hartford's normal year runs from 9°F January nights to 78°F July afternoons, with 51.4 inches of precipitation and 108 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.2°C, January lows of −13°C, July highs of 25°C, 1,305 mm of precipitation a year.
- NOAA stationHartford
- Station IDUSC00173570
- Location44.37°N 70.32°W
- Elevation705 ft (215 m)
On October 23, the normal high in Hartford is 53°F and the normal low 34°F, and the chance of measurable rain or snow is 41%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Hartford.
- Jan 26° 9°
- Feb 29° 10°
- Mar 38° 19°
- Apr 51° 31°
- May 64° 42°
- Jun 72° 51°
- Jul 78° 56°
- Aug 77° 55°
- Sep 69° 47°
- Oct 56° 36°
- Nov 44° 27°
- 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 at Hartford each month?
July is the warmest month, with normal highs of 78°F; January the coldest, with normal lows of 9°F. The most precipitation falls in October (5.59 in), the least in February (3.43 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 26°F | 9°F | 17.4°F | 3.66 | 21.8 | 12 | <1 | 31 | 9 h 10 min |
| February | 29°F | 10°F | 19.6°F | 3.43 | 29.0 | 11 | <1 | 28 | 10 h 30 min |
| March | 38°F | 19°F | 28.4°F | 4.15 | 22.2 | 11 | <1 | 29 | 11 h 50 min |
| April | 51°F | 31°F | 41.1°F | 4.64 | 6.4 | 12 | <1 | 19 | 13 h 20 min |
| May | 64°F | 42°F | 53.1°F | 3.86 | 0.3 | 14 | <1 | 3 | 14 h 40 min |
| June | 72°F | 51°F | 61.6°F | 4.95 | 0.0 | 15 | <1 | <1 | 15 h 30 min |
| July | 78°F | 56°F | 67.0°F | 4.20 | 0.0 | 13 | <1 | <1 | 15 h 10 min |
| August | 77°F | 55°F | 65.6°F | 3.98 | 0.0 | 12 | <1 | <1 | 14 h 10 min |
| September | 69°F | 47°F | 58.0°F | 3.85 | 0.0 | 10 | <1 | 1 | 12 h 40 min |
| October | 56°F | 36°F | 46.3°F | 5.59 | 1.2 | 13 | <1 | 11 | 11 h |
| November | 44°F | 27°F | 35.3°F | 4.54 | 5.7 | 12 | <1 | 23 | 9 h 40 min |
| December | 32°F | 17°F | 24.6°F | 4.53 | 21.1 | 13 | <1 | 30 | 8 h 50 min |
| Year (annual) | 53°F | 33°F | 43.2°F | 51.38 | 107.7 | 146 | 1 | 174 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | −3°C | −13°C | −8.1°C | 93 mm | 55 cm |
| February | −1°C | −12°C | −6.9°C | 87 mm | 74 cm |
| March | 3°C | −7°C | −2.0°C | 105 mm | 56 cm |
| April | 11°C | −1°C | 5.1°C | 118 mm | 16 cm |
| May | 18°C | 6°C | 11.7°C | 98 mm | 1 cm |
| June | 22°C | 11°C | 16.4°C | 126 mm | 0 cm |
| July | 25°C | 14°C | 19.4°C | 107 mm | 0 cm |
| August | 25°C | 13°C | 18.7°C | 101 mm | 0 cm |
| September | 21°C | 8°C | 14.4°C | 98 mm | 0 cm |
| October | 13°C | 2°C | 7.9°C | 142 mm | 3 cm |
| November | 6°C | −3°C | 1.8°C | 115 mm | 14 cm |
| December | 0°C | −8°C | −4.1°C | 115 mm | 54 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00173570; 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.
Which months are mildest at Hartford?
Normal highs sit between 65°F and 85°F in June, July, August and September. Of those, September has the fewest days with rain (10).
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 USC00173570.
When is the last frost at Hartford?
In Hartford, the last spring frost (32°F) comes after May 6 in half of years and after May 21 in one year in ten; the first autumn frost comes before October 3 in half of years and before September 23 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
- May 61 year in 10 after May 21; 9 in 10 after April 24
- First autumn frost, half of years before
- October 31 year in 10 before September 23; 9 in 10 before October 16
NOAA puts the median frost-free season at 148 days, and the season without a hard freeze (28°F) at 175 days.
A hard freeze (28°F) comes after April 24 in half of springs and before October 14 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Hartford in zone 5b in ZIP code 04220, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 5b: the coldest night of a typical year reaches −12°F (22 complete years).
Frost dates for every NOAA station in Maine · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00173570; 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.
How hot and how cold does it get at Hartford?
In a normal year in Hartford, 1 day a year reaches 90°F, 174 nights fall to 32°F or colder and 146 days bring measurable precipitation.
- Days at 90°F or more
- 1a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 174a normal year
- Days that stay below freezing
- 71high of 32°F or less
- Days with 0.01 inch of precipitation
- 146a normal year
- Days with 1 inch of snow or more
- 25a normal year
The highest temperature in this station's record (since 1998) is 93°F, on June 25, 2025; the lowest is −21°F, on February 15, 2003.
The wettest calendar year on that record is 2008, with 67.40 in; the snowiest season is 2000–01, with 168.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00173570; records: ACIS (NOAA Regional Climate Centers), station USC00173570. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Hartford?
Over a year 69% of the sunlight that would reach the ground under clear skies gets through the clouds at Hartford, 3.6 kWh per square metre a day. September is the sunniest month (76%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 64% | 1.6 |
| February | 67% | 2.5 |
| March | 69% | 3.6 |
| April | 67% | 4.6 |
| May | 66% | 5.2 |
| June | 68% | 5.6 |
| July | 74% | 5.7 |
| August | 76% | 5.2 |
| September | 76% | 4.2 |
| October | 66% | 2.6 |
| November | 64% | 1.7 |
| December | 60% | 1.2 |
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 many heating and cooling degree days does Hartford record?
A normal year at Hartford brings 8,167 heating degree days, 52% more than the median U.S. place (5,373), and 245 cooling degree days, 73% fewer than the median (908). Eight months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 1,849 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,474 | 0 |
| February | 1,273 | 0 |
| March | 1,135 | 0 |
| April | 719 | 0 |
| May | 377 | 8 |
| June | 140 | 40 |
| July | 38 | 100 |
| August | 54 | 74 |
| September | 232 | 22 |
| October | 581 | 1 |
| November | 891 | 0 |
| December | 1,254 | 0 |
| Year (annual) | 8,167 | 245 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00173570. 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.
Have recent years at Hartford been warmer than normal?
2025 averaged 43.3°F, 0.1°F above the 1991-2020 normal of 43.2°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. | Snow |
|---|---|---|---|---|
| 2021 | 45.1°F | +1.9°F | 40.02 | 68.1 |
| 2022 | 44.6°F | +1.4°F | 50.60 | 86.8 |
| 2023 | 45.8°F | +2.6°F | 65.48 | 106.7 |
| 2024 | 45.7°F | +2.5°F | 51.17 | 121.5 |
| 2025 | 43.3°F | +0.1°F | 45.47 | 85.8 |
Source: observed years: ACIS, station USC00173570. A year counts only with all twelve months complete.
How does Hartford's climate compare?
Hartford is warmer than 16 of the 42 places with their own NOAA record in Maine, and wetter than 38. Across the 7,247 U.S. stations with normals, its annual mean of 43.2°F is warmer than 13%.
In the Köppen classification computed from these normals, Hartford is Dfb: continental, no dry season, warm 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.
Questions about Hartford's climate
What is the coldest month at Hartford?
January, with a normal high of 26°F and a normal low of 9°F. The warmest is July (78°F by day, 56°F at night).
Does it snow at Hartford?
Yes: 108 inches in a normal year, falling on 44 days with 0.1 inch or more, the most in February (29.0 inches).
What is the rainiest month at Hartford?
October, with 5.59 in of precipitation in a normal year; the driest is February with 3.43 in.
What plant hardiness zone is Hartford in?
The USDA's 2023 map puts Hartford in zone 5b in ZIP code 04220, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −12°F (22 years, 1991-2020): zone 5b.
How late can frost come at Hartford?
In half of years the last 32°F night comes after May 6; in one year in ten it comes after May 21. Waiting until May 21 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Maine climateThe statewide normals and every place in the state
- Turner, ME7 miles from this station, 44.8°F a year
- Livermore Falls, ME11 miles from this station, 43.2°F a year
- Rumford, ME16 miles from this station, 44.0°F a year
- Lewiston, ME20 miles from this station, 46.3°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made