Grassflat, Pennsylvania Weather
Fireflies rise from the lawn. Day 76 of spring. Read this microseason across nine climate regions →
Grassflat weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Clear——79°44°—
- ThursdayJun 4Overcast——81°53°+2°
- FridayJun 5Overcast——81°57°0°
- SaturdayJun 6Showers64%0.13″82°59°+1°
- SundayJun 7Showers64%0.09″79°57°-3°
- MondayJun 8Light Drizzle——75°54°-4°
- TuesdayJun 9Partly Cloudy12%—79°48°+4°
Ozone at AQI 48 — peak already passed at 1 PM under clear skies. AQI up 15 in the last 6 hours — air quality is degrading. Levels should ease through evening.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 48 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 48
- UV peak
- 2.3 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 48
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
The higher the clouds, the finer the weather.
- Moonrise
- 3:06 AM
- Moonset
- 12:05 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Grassflat at a glance
- Today vs. normal: 4°F above the seasonal normal for this latitude
- Last frost: April 22 (climatological average for this latitude)
- Microseason: Jun 1–5
- Planting window: Harvest spring lettuce before it bolts. Sow heat-tolerant greens.
Right now in the garden
Peak growing season
As of June 3, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| January | — | — |
| February | — | — |
| March | — | — |
| April | lettuce, peas, spinach, radishes | — |
| May | lettuce, peas, spinach, radishes, tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, radishes |
| July | tomatoes, peppers, beans, squash | tomatoes, beans, summer squash |
| August | — | tomatoes, beans, summer squash |
| September | fall brassicas, garlic (overwinter), carrots | tomatoes, beans, summer squash |
| October | fall brassicas, garlic (overwinter), carrots | winter squash, tomatoes (last) |
| November | — | — |
| December | — | — |
A year in weather
Grassflat's warmest month is July (~68°F mean) and its coldest is January (~23°F). Rainfall peaks in September (4.5 inches) and bottoms out in February (2.6 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 23° | 3.2″ | 8 |
| February | 25° | 2.6″ | 7 |
| March | 34° | 3.6″ | 8 |
| April | 45° | 3.8″ | 9 |
| May | 55° | 4.1″ | 9 |
| June | 64° | 4.2″ | 9 |
| July | 68° | 4.0″ | 8 |
| August | 66° | 4.1″ | 7 |
| September | 59° | 4.5″ | 7 |
| October | 48° | 3.8″ | 7 |
| November | 37° | 3.3″ | 6 |
| December | 29° | 3.5″ | 8 |
Regional context
Grassflat's baseline climate, derived from NOAA NCEI 1991-2020 normals at the nearest reporting station, swings from a January mean of 23°F to a July mean of 68°F — a 44°F seasonal arc typical of the mid-latitude bands. Annual precipitation runs about 44.5 inches spread across roughly 93 days with measurable rain or snow each year.
Rainfall stays relatively even across the calendar: September tops out at 4.5 inches across 7.1 days with measurable rain, and February settles around 2.6 inches across 6.5 rainy days — a comparatively narrow seasonal range. The balanced distribution lines Grassflat up with places like Drifting, PA, Lanse, PA and Kylertown, PA, all of which run on overlapping storm tracks rather than a single seasonal moisture source.
The frost-sensitive growing window opens around mid-April, when overnight lows reliably clear freezing for cool-season crops like kale, peas, spinach, and parsnips. Warm-soil crops — tomatoes, peppers, eggplant — wait until soil temperatures reach the mid-50s°F, usually two weeks past the last-frost date. The window closes around mid-November, when overnight lows resume dipping below freezing and frost-tender plants need protection or harvest. These dates represent 30-year central tendencies; actual year-to-year variation can shift either bookend by 7-14 days, and local microclimate features within Grassflat — cold-air drainage on calm clear nights, slope aspect, distance from any nearby lake or river — can push the practical frost window earlier or later than the regional average.
Similar climates: Drifting, PA, Lanse, PA, Kylertown, PA, Winburne, PA, Casanova, PA.
Frequently asked
- When does it freeze in Grassflat?
- Grassflat's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Grassflat?
- September is the wettest month with about 4.5 inches of rain on average; the city receives roughly 44 inches annually.
- What is the warmest month in Grassflat?
- July is typically warmest, averaging about 68°F.
- What is the coldest month in Grassflat?
- January is typically coldest, averaging about 23°F.
- When can I start a vegetable garden in Grassflat?
- Cool-season crops (peas, lettuce) can be sown around the last spring frost (mid-April); warm-season crops (tomatoes, peppers) wait until 1–2 weeks after.
- How many rainy days does Grassflat get?
- Grassflat averages about 93 rainy days per year.
- What hardiness zone is Grassflat?
- Grassflat's USDA hardiness zone is determined by its lowest average winter temperature; check the USDA's online lookup with the city ZIP for the current zone designation.
Climate
Grassflat, Pennsylvania sits in a warm-summer humid continental climate zone. January means hover near 23°F while July averages 68°F — a 44°F seasonal swing.
Across the year, Grassflat receives about 44 inches of precipitation spread over roughly 93 rainy days.
The rhythm of the year is set by latitude (41.0°N), proximity to large water bodies, and elevation — all of which shape what grows here, when frost is likely, and what the weather story looks like day to day.