Jacobus, Pennsylvania Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Jacobus weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 3Mostly Clear——82°51°—
- ThursdayJun 4Overcast——86°58°+4°
- FridayJun 5Overcast——84°61°-2°
- SaturdayJun 6Overcast24%—85°64°+1°
- SundayJun 7Light Showers49%—76°64°-9°
- MondayJun 8Overcast14%—74°55°-2°
- TuesdayJun 9Partly Cloudy11%—75°49°+1°
Ozone at AQI 43 now. AQI up 17 in the last 6 hours — air quality is degrading. With UV 0.1 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 7 by mid-afternoon.
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 43 now. With UV 0.1 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 7 by mid-afternoon.
- Present
- AQI 43
- UV peak
- 0.1 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 7
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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 3:34 AM
- Moonset
- 1:07 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Jacobus at a glance
- Today vs. normal: 75°F — typical for the season
- Last frost: April 15 (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 4, 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
Jacobus's warmest month is July (~75°F mean) and its coldest is January (~31°F). Rainfall peaks in September (5.1 inches) and bottoms out in February (2.8 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 31° | 3.3″ | 6 |
| February | 34° | 2.8″ | 6 |
| March | 42° | 4.0″ | 7 |
| April | 54° | 3.6″ | 7 |
| May | 63° | 4.2″ | 8 |
| June | 71° | 4.3″ | 7 |
| July | 75° | 4.5″ | 7 |
| August | 74° | 4.0″ | 6 |
| September | 67° | 5.1″ | 6 |
| October | 56° | 3.9″ | 5 |
| November | 44° | 3.2″ | 6 |
| December | 36° | 3.5″ | 7 |
Regional context
Jacobus sits within a warm-summer humid continental climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Philadelphia, PA, Pittsburgh, PA, Allentown, PA, Harrisburg, PA, Lancaster, PA.
Frequently asked
- When does it freeze in Jacobus?
- Jacobus's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Jacobus?
- September is the wettest month with about 5.1 inches of rain on average; the city receives roughly 46 inches annually.
- What is the warmest month in Jacobus?
- July is typically warmest, averaging about 75°F.
- What is the coldest month in Jacobus?
- January is typically coldest, averaging about 31°F.
- When can I start a vegetable garden in Jacobus?
- 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 Jacobus get?
- Jacobus averages about 79 rainy days per year.
- What hardiness zone is Jacobus?
- Jacobus'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
Jacobus, Pennsylvania sits in a warm-summer humid continental climate zone. January means hover near 31°F while July averages 75°F — a 44°F seasonal swing.
Across the year, Jacobus receives about 46 inches of precipitation spread over roughly 79 rainy days.
The rhythm of the year is set by latitude (39.9°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.