Heidelberg, Pennsylvania Weather
Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Heidelberg weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Rain37%0.25″96°71°—
- SundayJul 5Showers79%0.14″90°72°-6°
- MondayJul 6T-storm w/ Hail71%0.09″83°68°-7°
- TuesdayJul 7Overcast36%—85°65°+2°
- WednesdayJul 8Overcast10%—88°63°+3°
- ThursdayJul 9Light Drizzle50%—90°69°+2°
- FridayJul 10Drizzle54%—82°68°-8°
AQI 59 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 22.9 µg/m³ (AQI 77) with a 0.99 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
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 38 now. With UV 3.7 peaking around 1 PM under partly cloudy skies, surface ozone likely climbs to AQI 13 around 1 PM.
- Present
- AQI 38
- UV peak
- 3.7 at 1 PM
- Sky at peak
- partly cloudy
- Projected peak
- AQI 13
PM × Wind × Precip
PM2.5 at 22.9 µg/m³ (AQI 77) with a 0.99 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.99
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- stagnant smoke
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).








































If the first of July be rainy weather, 'twill rain more or less for four weeks together.
- Moonrise
- 11:15 PM
- Moonset
- 10:24 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Heidelberg at a glance
- Today vs. normal: 6°F above the seasonal normal for this latitude
- Last frost: April 18 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — Heidelberg
- Sat96°71°37%
- Sun90°72°79%
- Mon83°68°71%
- Tue85°65°36%
- Wed88°63°10%
- Thu90°69°50%
- Fri82°68°54%
- Sat86°68°39%
- Sun83°65°30%
- Mon75°60°16%
- Tue80°61°15%
- Wed87°66°27%
- Thu93°70°19%
- Fri93°73°45%
- Sat83°70°35%
- Sun89°69°35%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of July 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 — Heidelberg
SPC has placed Heidelberg in the Slight Risk category for severe thunderstorms today.
- TODAYSLGTSlight Risk
- TOMORROWMRGLMarginal Risk
- DAY 3TSTMGeneral Thunderstorms
Scattered severe storms possible. A few tornadoes, hail, and damaging wind gusts possible.
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.
Microseason · July 1–5
Cicadas claim the afternoon
Annual cicada buzz begins, peaking in the heat of the day.
Day 185 of 365 · Wedge 37 of 72
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
The year in Heidelberg tops out in July (~73°F) and dips lowest in January (~28°F), with May wettest at 5.4 inches and February driest at 3.1 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 28° | 3.4″ | 20 |
| February | 31° | 3.1″ | 18 |
| March | 39° | 4.1″ | 19 |
| April | 51° | 4.3″ | 20 |
| May | 59° | 5.4″ | 19 |
| June | 68° | 4.7″ | 19 |
| July | 73° | 4.4″ | 18 |
| August | 73° | 4.0″ | 18 |
| September | 66° | 3.4″ | 16 |
| October | 55° | 3.2″ | 15 |
| November | 41° | 3.5″ | 18 |
| December | 32° | 3.9″ | 20 |
Frequently asked
- When does it freeze in Heidelberg?
- In Heidelberg, expect the last spring frost near mid-April; Heidelberg's first autumn frost comes around mid-November.
- What is the rainy season in Heidelberg?
- Heidelberg sees its heaviest rain in May (around 5.4 inches), part of roughly 47 inches a year.
- What is the warmest month in Heidelberg?
- July is Heidelberg's warmest month, averaging about 73°F.
- What is the coldest month in Heidelberg?
- Heidelberg bottoms out in January, with a mean near 28°F.
- When can I start a vegetable garden in Heidelberg?
- Frost-hardy sowings begin at mid-April in Heidelberg; warm-season starts follow two weeks on.
- How many rainy days does Heidelberg get?
- Heidelberg averages about 221 days with measurable rain or snow each year.
- What hardiness zone is Heidelberg?
- Heidelberg's USDA zone comes from its January mean (28°F); enter the ZIP on the USDA lookup for the number.
- What is the 10-day forecast for Heidelberg?
- Heidelberg's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Heidelberg?
- See this week's day-by-day rain chances for Heidelberg in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Heidelberg?
- Current conditions for Heidelberg and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Heidelberg forecast updated?
- The Heidelberg forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Heidelberg?
- Today's sunrise and sunset times for Heidelberg are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Heidelberg?
- The next few days in Heidelberg's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Heidelberg, Pennsylvania occupies a warm-summer humid continental zone, with January means near 28°F and July around 73°F — a 45°F swing.
Yearly precipitation in Heidelberg totals around 47 inches, spread over about 221 days of rain or snow.
The 45°F gap between Heidelberg's summer and winter, at 40.4°N, shapes Heidelberg's frost calendar.
ZIP codes in Heidelberg
- 15106