Blue Marsh Lake, Pennsylvania climate: Climate normals at a NOAA weather station
Blue Marsh Lake's normal year runs from 20°F January nights to 85°F July afternoons, with 48.4 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 10.8°C, January lows of −7°C, July highs of 30°C, 1,229 mm of precipitation a year.
- NOAA stationBlue Marsh Lake
- Station IDUSC00360785
- Location40.38°N 76.03°W
- Elevation350 ft (107 m)
On October 23, the normal high in Blue Marsh Lake is 62°F and the normal low 40°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Blue Marsh Lake.
- Jan 37° 20°
- Feb 40° 21°
- Mar 49° 29°
- Apr 62° 38°
- May 72° 49°
- Jun 80° 58°
- Jul 85° 63°
- Aug 83° 62°
- Sep 77° 54°
- Oct 65° 42°
- Nov 53° 33°
- 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 at Blue Marsh Lake each month?
July is the warmest month, with normal highs of 85°F; January the coldest, with normal lows of 20°F. The most precipitation falls in July (5.15 in), the least in February (2.59 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 37°F | 20°F | 28.4°F | 3.32 | – | <1 | 27 | 9 h 40 min |
| February | 40°F | 21°F | 30.3°F | 2.59 | – | <1 | 25 | 10 h 40 min |
| March | 49°F | 29°F | 38.7°F | 3.88 | – | <1 | 20 | 11 h 50 min |
| April | 62°F | 38°F | 50.0°F | 3.81 | – | <1 | 7 | 13 h 10 min |
| May | 72°F | 49°F | 60.3°F | 3.83 | – | 1 | 1 | 14 h 20 min |
| June | 80°F | 58°F | 69.4°F | 4.83 | – | 3 | <1 | 15 h |
| July | 85°F | 63°F | 74.3°F | 5.15 | – | 7 | <1 | 14 h 50 min |
| August | 83°F | 62°F | 72.5°F | 4.64 | – | 4 | <1 | 13 h 50 min |
| September | 77°F | 54°F | 65.3°F | 5.01 | – | 1 | <1 | 12 h 30 min |
| October | 65°F | 42°F | 53.3°F | 4.30 | – | <1 | 4 | 11 h 10 min |
| November | 53°F | 33°F | 42.6°F | 3.24 | – | <1 | 16 | 10 h |
| December | 42°F | 25°F | 33.6°F | 3.77 | – | <1 | 25 | 9 h 20 min |
| Year (annual) | 62°F | 41°F | 51.5°F | 48.37 | – | 16 | 125 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 3°C | −7°C | −2.0°C | 84 mm |
| February | 4°C | −6°C | −0.9°C | 66 mm |
| March | 9°C | −2°C | 3.7°C | 99 mm |
| April | 17°C | 4°C | 10.0°C | 97 mm |
| May | 22°C | 9°C | 15.7°C | 97 mm |
| June | 27°C | 15°C | 20.8°C | 123 mm |
| July | 30°C | 17°C | 23.5°C | 131 mm |
| August | 29°C | 16°C | 22.5°C | 118 mm |
| September | 25°C | 12°C | 18.5°C | 127 mm |
| October | 18°C | 6°C | 11.8°C | 109 mm |
| November | 11°C | 0°C | 5.9°C | 82 mm |
| December | 6°C | −4°C | 0.9°C | 96 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Hamburg (12 miles away), gets 21 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00360785; 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 Blue Marsh Lake?
Normal highs sit between 65°F and 85°F in May, June, August and September.
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 USC00360785.
When is the last frost at Blue Marsh Lake?
In Blue Marsh Lake, the last spring frost (32°F) comes after April 26 in half of years and after May 12 in one year in ten; the first autumn frost comes before October 19 in half of years and before October 5 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 261 year in 10 after May 12; 9 in 10 after April 11
- First autumn frost, half of years before
- October 191 year in 10 before October 5; 9 in 10 before November 3
NOAA puts the median frost-free season at 176 days, and the season without a hard freeze (28°F) at 202 days.
A hard freeze (28°F) comes after April 12 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Blue Marsh Lake in zone 7a in ZIP code 19533, 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 7a: the coldest night of a typical year reaches 2°F (21 complete years).
Frost dates for every NOAA station in Pennsylvania · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00360785; 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 Blue Marsh Lake?
In a normal year in Blue Marsh Lake, 16 days a year reach 90°F and 125 nights fall to 32°F or colder.
- Days at 90°F or more
- 16a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 125a normal year
- Days that stay below freezing
- 26high of 32°F or less
Source: NOAA NCEI 1991-2020 annual normals, station USC00360785.
How sunny is it at Blue Marsh Lake?
Over a year 71% of the sunlight that would reach the ground under clear skies gets through the clouds at Blue Marsh Lake, 3.9 kWh per square metre a day. July is the sunniest month (79%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 63% | 1.8 |
| February | 66% | 2.7 |
| March | 66% | 3.6 |
| April | 69% | 4.8 |
| May | 69% | 5.3 |
| June | 75% | 6.0 |
| July | 79% | 6.0 |
| August | 76% | 5.2 |
| September | 74% | 4.2 |
| October | 68% | 2.9 |
| November | 69% | 2.1 |
| December | 60% | 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 many heating and cooling degree days does Blue Marsh Lake record?
A normal year at Blue Marsh Lake brings 5,717 heating degree days, 6% more than the median U.S. place (5,373), and 843 cooling degree days, 7% 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 3,139 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,136 | 0 |
| February | 973 | 0 |
| March | 816 | 0 |
| April | 454 | 5 |
| May | 191 | 44 |
| June | 34 | 164 |
| July | 3 | 291 |
| August | 6 | 237 |
| September | 85 | 92 |
| October | 373 | 10 |
| November | 674 | 0 |
| December | 975 | 0 |
| Year (annual) | 5,717 | 843 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00360785. 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 Blue Marsh Lake been warmer than normal?
2023 averaged 53.2°F, 1.7°F above the 1991-2020 normal of 51.5°F. 2 of the 2 complete years since 2022 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2022 | 51.9°F | +0.4°F | 45.74 |
| 2023 | 53.2°F | +1.7°F | 46.44 |
Source: observed years: ACIS, station USC00360785. A year counts only with all twelve months complete.
How does Blue Marsh Lake's climate compare?
Blue Marsh Lake is warmer than 67 of the 108 places with their own NOAA record in Pennsylvania, and wetter than 88. Across the 7,247 U.S. stations with normals, its annual mean of 51.5°F is warmer than 47%.
In the Köppen classification computed from these normals, Blue Marsh Lake 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 Blue Marsh Lake 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.
- Sinking Spring, PA4,327 people · 4 mi S
- Newmanstown, PA3,270 people · 10 mi W
- Womelsdorf, PA2,952 people · 8 mi W
- Wernersville, PA2,807 people · 5 mi SW
- Reinholds, PA2,226 people · 9 mi SW
- Robesonia, PA2,173 people · 6 mi W
- Adamstown, PA1,960 people · 10 mi S
- Bernville, PA914 people · 6 mi NW
- Dauberville, PA691 people · 6 mi N
- Stouchsburg, PA412 people · 11 mi W
- Rehrersburg, PA231 people · 13 mi NW
- New Schaefferstown, PA210 people · 9 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.
Questions about Blue Marsh Lake's climate
What is the coldest month at Blue Marsh Lake?
January, with a normal high of 37°F and a normal low of 20°F. The warmest is July (85°F by day, 63°F at night).
Does it snow at Blue Marsh Lake?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Hamburg (12 miles away), records 21 inches of snow in a normal year.
What is the rainiest month at Blue Marsh Lake?
July, with 5.15 in of precipitation in a normal year; the driest is February with 2.59 in.
What plant hardiness zone is Blue Marsh Lake in?
The USDA's 2023 map puts Blue Marsh Lake in zone 7a in ZIP code 19533, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches 2°F (21 years, 1991-2020): zone 7a.
How late can frost come at Blue Marsh Lake?
In half of years the last 32°F night comes after April 26; 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
- Pennsylvania climateThe statewide normals and every place in the state
- Reading, PA3 miles from this station, 53.7°F a year
- Hamburg, PA12 miles from this station, 52.2°F a year
- Hopewell Morgantown, PA17 miles from this station, 52.0°F a year
- Rodale Research Center, PA20 miles from this station, 51.5°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made