Harrisburg, Pennsylvania Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Harrisburg weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——88°54°—
- FridayJun 5Overcast——92°61°+4°
- SaturdayJun 6Drizzle34%0.02″88°65°-4°
- SundayJun 7Showers34%0.32″87°64°-1°
- MondayJun 8Overcast——76°57°-11°
- TuesdayJun 9Overcast——82°54°+6°
- WednesdayJun 10Partly Cloudy13%—87°59°+5°
Ozone at AQI 78 — peak already passed at 1 PM under clear skies. AQI up 23 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 78 — peak already passed at 1 PM under clear skies. Levels should ease through evening.
- Present
- AQI 78
- UV peak
- 5.9 at earlier today
- Sky at peak
- clear
- Projected peak
- AQI 78
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
- 3:36 AM
- Moonset
- 1:06 PM
- In sign
- ♒︎ Aquarius
Fireflies rise from the lawn
Harrisburg at a glance
- Today vs. normal: 13°F above the seasonal normal for this latitude
- Last frost: April 18 (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.
SPC Convective Outlook
Storm Prediction Center — Harrisburg
SPC has placed Harrisburg in the Marginal Risk category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3MRGLMarginal Risk
Isolated severe storms possible. Limited threat for hail or damaging wind.
Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.
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
July brings Harrisburg's warmest temperatures at around 75°F mean, while January delivers the coldest at about 29°F. Precipitation follows a similar pattern, with July recording the highest rainfall at 4.8 inches and February seeing the least at 2.8 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 29° | 2.9″ | 6 |
| February | 31° | 2.8″ | 5 |
| March | 39° | 3.9″ | 6 |
| April | 51° | 3.9″ | 8 |
| May | 61° | 4.0″ | 9 |
| June | 71° | 4.0″ | 8 |
| July | 75° | 4.8″ | 7 |
| August | 73° | 4.3″ | 8 |
| September | 65° | 4.6″ | 6 |
| October | 53° | 3.8″ | 7 |
| November | 42° | 2.9″ | 6 |
| December | 34° | 3.4″ | 7 |
Regional context
Harrisburg belongs to the warm-summer humid continental climate region, sharing similar temperature ranges, seasonal patterns, and growing conditions with other nearby cities in this climate group.
Similar climates: Philadelphia, PA, Pittsburgh, PA, Allentown, PA, Lancaster, PA, Scranton, PA.
Naturalist notes
American robins begin their morning chorus in earnest during late April, coinciding with the warming soil temperatures after the last frost.
Tulip trees start leafing out in early May when nighttime temperatures consistently stay above 45°F.
Frequently asked
- When does it freeze in Harrisburg?
- The last spring frost in Harrisburg typically occurs around mid-April, while the first fall frost arrives around mid-November.
- What is the rainy season in Harrisburg?
- July records the highest monthly rainfall at about 4.8 inches on average, with the city receiving roughly 45 inches annually.
- What is the warmest month in Harrisburg?
- July typically brings the warmest temperatures, averaging about 75°F.
- What is the coldest month in Harrisburg?
- January typically records the coldest temperatures, averaging about 29°F.
- When can I start a vegetable garden in Harrisburg?
- Cool-season crops like peas and lettuce can be planted around the last spring frost in mid-April, while warm-season crops such as tomatoes and peppers should wait until 1–2 weeks after.
- How many rainy days does Harrisburg get?
- Harrisburg averages about 82 rainy days per year.
- What hardiness zone is Harrisburg?
- Harrisburg's USDA hardiness zone depends on its lowest average winter temperature; the USDA's online lookup tool using the city ZIP code provides the current zone designation.
Climate
Harrisburg, Pennsylvania experiences a warm-summer humid continental climate zone. January temperatures hover near 29°F while July averages 75°F, creating a 46°F seasonal swing.
Annual precipitation totals about 45 inches, distributed across roughly 82 rainy days throughout the year.
Several factors control the local weather patterns: latitude at 40.3°N, proximity to large water bodies, and elevation. These elements determine what grows in the area, frost timing, and daily weather conditions.