New Castle, Pennsylvania climate: Normal weather by month, frost dates and records
New Castle's normal year runs from 19°F January nights to 86°F July afternoons, with 41.8 inches of precipitation and 28 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, 1,061 mm of precipitation a year.
- NOAA stationNew Castle (1 mi N)
- Station IDUSC00366233
- Location41.02°N 80.36°W
- Elevation825 ft (252 m)
- Population21,332
On October 23, the normal high in New Castle is 63°F and the normal low 39°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 New Castle.
- Jan 37° 19°
- Feb 40° 20°
- Mar 49° 27°
- Apr 63° 36°
- May 73° 47°
- Jun 82° 56°
- Jul 86° 60°
- Aug 85° 59°
- Sep 79° 52°
- Oct 66° 41°
- Nov 53° 32°
- Dec 42° 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 New Castle each month?
July is the warmest month, with normal highs of 86°F; January the coldest, with normal lows of 19°F. The most precipitation falls in July (4.55 in), the least in February (2.20 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 | 37°F | 19°F | 27.9°F | 2.86 | 10.1 | 16 | <1 | 27 | 9 h 30 min |
| February | 40°F | 20°F | 29.6°F | 2.20 | 7.7 | 12 | <1 | 25 | 10 h 40 min |
| March | 49°F | 27°F | 37.8°F | 3.08 | 3.7 | 12 | <1 | 23 | 11 h 50 min |
| April | 63°F | 36°F | 49.4°F | 3.65 | 0.3 | 15 | <1 | 12 | 13 h 20 min |
| May | 73°F | 47°F | 60.1°F | 3.89 | 0.0 | 14 | 1 | 1 | 14 h 30 min |
| June | 82°F | 56°F | 68.8°F | 4.47 | 0.0 | 13 | 4 | <1 | 15 h 10 min |
| July | 86°F | 60°F | 73.1°F | 4.55 | 0.0 | 12 | 8 | <1 | 14 h 50 min |
| August | 85°F | 59°F | 71.9°F | 3.91 | 0.0 | 11 | 7 | <1 | 13 h 50 min |
| September | 79°F | 52°F | 65.4°F | 3.86 | 0.0 | 11 | 2 | <1 | 12 h 30 min |
| October | 66°F | 41°F | 53.8°F | 3.22 | 0.0 | 12 | <1 | 5 | 11 h 10 min |
| November | 53°F | 32°F | 42.4°F | 2.96 | 0.8 | 13 | <1 | 17 | 10 h |
| December | 42°F | 25°F | 33.3°F | 3.13 | 4.9 | 14 | <1 | 24 | 9 h 20 min |
| Year (annual) | 63°F | 39°F | 51.1°F | 41.78 | 27.5 | 156 | 21 | 134 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 3°C | −7°C | −2.3°C | 73 mm | 26 cm |
| February | 4°C | −7°C | −1.3°C | 56 mm | 20 cm |
| March | 10°C | −3°C | 3.2°C | 78 mm | 9 cm |
| April | 17°C | 2°C | 9.7°C | 93 mm | 1 cm |
| May | 23°C | 8°C | 15.6°C | 99 mm | 0 cm |
| June | 28°C | 13°C | 20.4°C | 114 mm | 0 cm |
| July | 30°C | 16°C | 22.8°C | 116 mm | 0 cm |
| August | 29°C | 15°C | 22.2°C | 99 mm | 0 cm |
| September | 26°C | 11°C | 18.6°C | 98 mm | 0 cm |
| October | 19°C | 5°C | 12.1°C | 82 mm | 0 cm |
| November | 12°C | 0°C | 5.8°C | 75 mm | 2 cm |
| December | 5°C | −4°C | 0.7°C | 80 mm | 12 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00366233; 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 New Castle?
Normal highs sit between 65°F and 85°F in May, June, August, September and October. Of those, September has the fewest days with rain (11).
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 USC00366233.
When is the last frost in New Castle?
In New Castle, the last spring frost (32°F) comes after April 30 in half of years and after May 19 in one year in ten; the first autumn frost comes before October 23 in half of years and before October 6 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 301 year in 10 after May 19; 9 in 10 after April 17
- First autumn frost, half of years before
- October 231 year in 10 before October 6; 9 in 10 before November 4
NOAA puts the median frost-free season at 175 days, and the season without a hard freeze (28°F) at 198 days.
A hard freeze (28°F) comes after April 20 in half of springs and before November 2 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts New Castle in zone 6a in ZIP code 16101, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, New Castle's NOAA station is in zone 6b: the coldest night of a typical year reaches −5°F (22 complete years); the map interpolates between stations and terrain, so the station and the ZIP area can differ by half a zone.
Frost dates for every NOAA station in Pennsylvania · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00366233; 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 in New Castle?
In a normal year in New Castle, 21 days a year reach 90°F, 134 nights fall to 32°F or colder and 156 days bring measurable precipitation.
- Days at 90°F or more
- 21a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 134a normal year
- Days that stay below freezing
- 30high of 32°F or less
- Days with 0.01 inch of precipitation
- 156a normal year
- Days with 1 inch of snow or more
- 11a normal year
The highest temperature in this station's record (since 1894) is 105°F, on July 23, 2011; the lowest is −27°F, on January 19, 1994.
The wettest calendar year on that record is 2004, with 54.73 in; the snowiest season is 1950–51, with 67.1 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00366233; records: ACIS (NOAA Regional Climate Centers), station USC00366233. Records use complete months only; a month missing more than three days is left out.
How sunny is New Castle?
Over a year 68% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around New Castle, 3.6 kWh per square metre a day. July is the sunniest month (77%) and December the cloudiest (47%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 51% | 1.4 |
| February | 57% | 2.3 |
| March | 60% | 3.3 |
| April | 65% | 4.5 |
| May | 69% | 5.3 |
| June | 74% | 5.9 |
| July | 77% | 5.9 |
| August | 77% | 5.2 |
| September | 74% | 4.2 |
| October | 64% | 2.7 |
| November | 61% | 1.8 |
| December | 47% | 1.1 |
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 New Castle need?
A normal year in New Castle brings 5,800 heating degree days, 8% more than the median U.S. place (5,373), and 781 cooling degree days, 14% 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 3,088 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,149 | 0 |
| February | 991 | 0 |
| March | 842 | 0 |
| April | 473 | 5 |
| May | 199 | 46 |
| June | 38 | 152 |
| July | 3 | 256 |
| August | 7 | 219 |
| September | 79 | 91 |
| October | 360 | 11 |
| November | 678 | 0 |
| December | 981 | 0 |
| Year (annual) | 5,800 | 781 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00366233. 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 New Castle been warmer than normal lately?
Over 99 complete years from 1866 to 2016, the station's annual mean temperature rose at a fitted 0.8°F per century (+0.05°C per decade). A fitted rate summarizes the whole record; single years swing well above and below it.
Source: trend: NOAA GHCN-Monthly v4. A year counts only with all twelve months complete.
How does New Castle's climate compare?
New Castle is warmer than 59 of the other 107 places with their own NOAA record in Pennsylvania, and wetter than 23. Across the 7,247 U.S. stations with normals, its annual mean of 51.1°F is warmer than 45%.
In the Köppen classification computed from these normals, New Castle 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 New Castle share this climate record?
26 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.
- Struthers, OH9,891 people · 12 mi W
- Campbell, OH7,751 people · 13 mi W
- Canfield, OH7,628 people · 21 mi W
- Hubbard, OH7,565 people · 14 mi NW
- Columbiana, OH6,773 people · 18 mi SW
- Poland, OH2,423 people · 13 mi W
- Oakwood, PA2,263 people · 1 mi SW
- New Wilmington, PA2,089 people · 7 mi N
- Woodworth, OH1,921 people · 16 mi W
- New Castle Northwest, PA1,589 people · 0 mi NE
- New Middletown, OH1,489 people · 11 mi W
- Oakland, PA1,309 people · 2 mi S
- North Lima, OH1,139 people · 17 mi W
- Bessemer, PA1,043 people · 7 mi SW
- Lowellville, OH986 people · 10 mi W
- West Pittsburg, PA949 people · 6 mi S
- New Springfield, OH639 people · 14 mi SW
- South New Castle, PA636 people · 3 mi S
- Mount Jackson, PA483 people · 5 mi SW
- Hillsville, PA459 people · 7 mi W
- Frizzleburg, PA390 people · 6 mi NW
- Petersburg, OH308 people · 12 mi SW
- Maplewood Park, OH251 people · 14 mi NW
- Chewton, PA243 people · 9 mi S
- Edinburg, PA160 people · 4 mi W
- S.N.P.J., PA15 people · 9 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.
Questions about New Castle's climate
What is the coldest month in New Castle?
January, with a normal high of 37°F and a normal low of 19°F. The warmest is July (86°F by day, 60°F at night).
Does it snow in New Castle?
Yes: 28 inches in a normal year, falling on 22 days with 0.1 inch or more, the most in January (10.1 inches).
What is the rainiest month in New Castle?
July, with 4.55 in of precipitation in a normal year; the driest is February with 2.20 in.
What plant hardiness zone is New Castle in?
The USDA's 2023 map puts New Castle in zone 6a in ZIP code 16101, the nearest ZIP area. By the same method at New Castle's NOAA station, the coldest night of a typical year reaches −5°F (22 years, 1991-2020): zone 6b.
How late can frost come in New Castle?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 19. Waiting until May 19 leaves about a one-in-ten chance of a later frost.
Nearby and next
- New Castle in OctoberThis month day by day, its records and recent years
- Pennsylvania climateThe statewide normals and every place in the state
- Mercer, PA16 miles from this station, 48.5°F a year
- Slippery Rock, PA16 miles from this station, 48.1°F a year
- Beaver Falls, PA18 miles from this station, 50.4°F a year
- Youngstown, OH23 miles from this station, 49.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made