Grafton, New Hampshire climate: Climate normals at a NOAA weather station
Grafton's normal year runs from 7°F January nights to 80°F July afternoons, with 40.2 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 6.2°C, January lows of −14°C, July highs of 26°C, 1,020 mm of precipitation a year.
- NOAA stationGrafton
- Station IDUSC00273530
- Location43.57°N 71.95°W
- Elevation830 ft (253 m)
On October 24, the normal high in Grafton is 55°F and the normal low 31°F, and the chance of measurable rain or snow is 33%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Grafton.
- Jan 29° 7°
- Feb 32° 7°
- Mar 40° 17°
- Apr 54° 28°
- May 66° 40°
- Jun 75° 50°
- Jul 80° 54°
- Aug 78° 53°
- Sep 71° 45°
- Oct 58° 33°
- Nov 45° 25°
- Dec 34° 15°
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 Grafton each month?
July is the warmest month, with normal highs of 80°F; January the coldest, with normal lows of 7°F. The most precipitation falls in October (4.51 in), the least in February (2.55 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 29°F | 7°F | 18.2°F | 2.93 | 12 | <1 | 31 | 9 h 20 min |
| February | 32°F | 7°F | 19.6°F | 2.55 | 9 | <1 | 27 | 10 h 30 min |
| March | 40°F | 17°F | 28.6°F | 3.05 | 11 | <1 | 30 | 11 h 50 min |
| April | 54°F | 28°F | 41.3°F | 3.20 | 10 | <1 | 23 | 13 h 20 min |
| May | 66°F | 40°F | 52.8°F | 3.18 | 10 | <1 | 9 | 14 h 40 min |
| June | 75°F | 50°F | 62.4°F | 4.21 | 10 | 1 | 1 | 15 h 20 min |
| July | 80°F | 54°F | 66.8°F | 3.89 | 10 | 2 | <1 | 15 h 10 min |
| August | 78°F | 53°F | 65.5°F | 3.32 | 8 | 2 | <1 | 14 h |
| September | 71°F | 45°F | 57.7°F | 3.23 | 10 | <1 | 5 | 12 h 30 min |
| October | 58°F | 33°F | 45.4°F | 4.51 | 9 | <1 | 20 | 11 h 10 min |
| November | 45°F | 25°F | 35.3°F | 3.11 | 11 | <1 | 24 | 9 h 40 min |
| December | 34°F | 15°F | 24.5°F | 2.98 | 11 | <1 | 30 | 9 h |
| Year (annual) | 55°F | 31°F | 43.2°F | 40.16 | 123 | 5 | 199 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −2°C | −14°C | −7.7°C | 74 mm |
| February | 0°C | −14°C | −6.9°C | 65 mm |
| March | 5°C | −8°C | −1.9°C | 77 mm |
| April | 12°C | −2°C | 5.2°C | 81 mm |
| May | 19°C | 4°C | 11.6°C | 81 mm |
| June | 24°C | 10°C | 16.9°C | 107 mm |
| July | 26°C | 12°C | 19.3°C | 99 mm |
| August | 25°C | 12°C | 18.6°C | 84 mm |
| September | 22°C | 7°C | 14.3°C | 82 mm |
| October | 14°C | 0°C | 7.4°C | 115 mm |
| November | 7°C | −4°C | 1.8°C | 79 mm |
| December | 1°C | −9°C | −4.2°C | 76 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Mount Sunapee (17 miles away), gets 85 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00273530; 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 Grafton?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, August has the fewest days with rain (8).
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 USC00273530.
When is the last frost at Grafton?
In Grafton, the last spring frost (32°F) comes after May 21 in half of years and after June 5 in one year in ten; the first autumn frost comes before September 26 in half of years and before September 12 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 211 year in 10 after June 5; 9 in 10 after May 7
- First autumn frost, half of years before
- September 261 year in 10 before September 12; 9 in 10 before October 7
NOAA puts the median frost-free season at 127 days, and the season without a hard freeze (28°F) at 150 days.
A hard freeze (28°F) comes after May 8 in half of springs and before October 5 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Grafton in zone 5a in ZIP code 03240, the nearest ZIP area.
Frost dates for every NOAA station in New Hampshire · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00273530; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. 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 Grafton?
In a normal year in Grafton, 5 days a year reach 90°F, 199 nights fall to 32°F or colder and 123 days bring measurable precipitation.
- Days at 90°F or more
- 5a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 199a normal year
- Days that stay below freezing
- 57high of 32°F or less
- Days with 0.01 inch of precipitation
- 123a normal year
The highest temperature in this station's record (since 1893) is 99°F, on June 28, 1901; the lowest is −40°F, on January 21, 1994.
The wettest calendar year on that record is 1996, with 52.83 in; the snowiest season is 1968–69, with 141.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00273530; records: ACIS (NOAA Regional Climate Centers), station USC00273530. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Grafton?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds at Grafton, 3.7 kWh per square metre a day. August is the sunniest month (77%) and December the cloudiest (62%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 66% | 1.7 |
| February | 68% | 2.5 |
| March | 68% | 3.6 |
| April | 68% | 4.6 |
| May | 67% | 5.2 |
| June | 70% | 5.6 |
| July | 76% | 5.8 |
| August | 77% | 5.2 |
| September | 77% | 4.2 |
| October | 66% | 2.7 |
| November | 66% | 1.8 |
| December | 62% | 1.3 |
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 Grafton record?
A normal year at Grafton brings 8,180 heating degree days, 52% more than the median U.S. place (5,373), and 261 cooling degree days, 71% 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 1,846 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,452 | 0 |
| February | 1,272 | 0 |
| March | 1,127 | 0 |
| April | 712 | 1 |
| May | 384 | 6 |
| June | 130 | 50 |
| July | 46 | 102 |
| August | 64 | 80 |
| September | 240 | 22 |
| October | 608 | 0 |
| November | 890 | 0 |
| December | 1,255 | 0 |
| Year (annual) | 8,180 | 261 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00273530. 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.
How does Grafton's climate compare?
Grafton is warmer than 6 of the 28 places with their own NOAA record in New Hampshire, and wetter than 5. 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, Grafton 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 Grafton's climate
What is the coldest month at Grafton?
January, with a normal high of 29°F and a normal low of 7°F. The warmest is July (80°F by day, 54°F at night).
Does it snow at Grafton?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Mount Sunapee (17 miles away), records 85 inches of snow in a normal year.
What is the rainiest month at Grafton?
October, with 4.51 in of precipitation in a normal year; the driest is February with 2.55 in.
What plant hardiness zone is Grafton in?
The USDA's 2023 map puts Grafton in zone 5a in ZIP code 03240, the nearest ZIP area.
How late can frost come at Grafton?
In half of years the last 32°F night comes after May 21; in one year in ten it comes after June 5. Waiting until June 5 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New Hampshire climateThe statewide normals and every place in the state
- Franklin, NH16 miles from this station, 45.2°F a year
- Mount Sunapee, NH17 miles from this station, 45.5°F a year
- Newport, NH17 miles from this station, 44.3°F a year
- Salisbury, NH18 miles from this station, 45.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made