Rosemont, Pennsylvania Weather
Cicadas claim the afternoon. Day 14 of summer. Read this microseason across nine climate regions →
Rosemont weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJul 4Light Drizzle38%—99°75°—
- SundayJul 5Drizzle44%0.08″92°72°-7°
- MondayJul 6Thunderstorm94%0.27″75°70°-17°
- TuesdayJul 7Drizzle75%—78°68°+3°
- WednesdayJul 8Light Drizzle18%—79°65°+1°
- ThursdayJul 9Overcast16%—89°67°+10°
- FridayJul 10Light Drizzle38%—87°71°-2°
AQI 71 (Moderate), driven by Ozone. AQI up 7 over the last 6 hours (gradual rise). Ozone at AQI 128 now. With UV 8.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 142 around 1 PM.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion during the projected peak around 10 PM.
What's driving it
Ozone × UV × Sky
Ozone at AQI 128 now. With UV 8.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 142 around 1 PM.
- Present
- AQI 128
- UV peak
- 8.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 142
PM × Wind × Precip
PM2.5 at 9.1 µg/m³, PM10 at 9.7 µg/m³ — typical background levels with no transport signature.
- PM2.5/PM10
- 0.94
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- background
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
- 10:55 PM
- Moonset
- 10:05 AM
- In sign
- ♓︎ Pisces
Cicadas claim the afternoon
Rosemont at a glance
- Today vs. normal: 26°F above the seasonal normal for this latitude
- Last frost: April 16 (climatological average for this latitude)
- Microseason: Jul 1–5
- Planting window: Harvest early potatoes. Begin drying onions on the surface.
16-Day Forecast — Rosemont
- Sat99°75°38%
- Sun92°72°44%
- Mon75°70°94%
- Tue78°68°75%
- Wed79°65°18%
- Thu89°67°16%
- Fri87°71°38%
- Sat87°73°33%
- Sun82°69°28%
- Mon80°69°22%
- Tue87°67°21%
- Wed89°67°26%
- Thu89°71°29%
- Fri93°75°32%
- Sat92°73°26%
- Sun89°74°24%
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 — Rosemont
SPC has placed Rosemont in the Enhanced Risk category for severe thunderstorms today.
- TODAYENHEnhanced Risk
- TOMORROWSLGTSlight Risk
- DAY 3TSTMGeneral Thunderstorms
Numerous severe storms likely. Tornadoes, large hail, and damaging wind gusts possible across the area. Track NWS warnings if storms develop.
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
In Rosemont, July runs warmest near 77°F and January coldest around 31°F, while December is the wettest month (4.2 inches) and February the driest (2.9 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 31° | 3.4″ | 13 |
| February | 33° | 2.9″ | 12 |
| March | 42° | 3.7″ | 15 |
| April | 53° | 3.9″ | 17 |
| May | 61° | 3.7″ | 17 |
| June | 71° | 3.7″ | 17 |
| July | 77° | 3.3″ | 16 |
| August | 75° | 4.0″ | 17 |
| September | 69° | 3.7″ | 13 |
| October | 58° | 3.0″ | 11 |
| November | 45° | 3.6″ | 13 |
| December | 36° | 4.2″ | 13 |
Regional context
By the nearest station's NOAA NCEI 1991-2020 normals, Rosemont sees 31°F Januarys and 77°F Julys, a 46°F range, plus around 43.1 inches of precipitation across 173 days.
No season owns Rosemont's rain: December reaches 4.2 inches across 13.0 days and February keeps 2.9 inches on 12.4, an even spread through Rosemont's year. That even rhythm groups Rosemont with places like Bryn Mawr, PA, Villanova, PA and Haverford College, PA.
The cool-season window in Rosemont starts at mid-April, when nights stop freezing — think peas, lettuce, spinach, and radishes. Hold Rosemont's tender crops — tomatoes, peppers, basil — until 10-14 days past Rosemont's last frost. It shuts near mid-November, when freezes return to Rosemont and tender plants need cover. Within Rosemont, cold-air pooling chills low spots by 5-10°F, shifting Rosemont's local frost dates.
Similar climates: Bryn Mawr, PA, Villanova, PA, Haverford College, PA, Saint Davids, PA, Ardmore, PA.
Frequently asked
- When does it freeze in Rosemont?
- Rosemont's last spring frost lands near mid-April, and in Rosemont the first fall frost follows around mid-November.
- What is the rainy season in Rosemont?
- Rosemont sees its heaviest rain in December (around 4.2 inches), part of roughly 43 inches a year.
- What is the warmest month in Rosemont?
- July is Rosemont's warmest month, averaging about 77°F.
- What is the coldest month in Rosemont?
- Rosemont bottoms out in January, with a mean near 31°F.
- When can I start a vegetable garden in Rosemont?
- Time tomatoes in Rosemont for two weeks after mid-April; peas and greens start at Rosemont's frost line.
- How many rainy days does Rosemont get?
- Rosemont records around 173 days of measurable precipitation annually.
- What hardiness zone is Rosemont?
- Rosemont sits in the USDA zone set by January lows near 31°F; the USDA ZIP tool gives the band.
- What is the 10-day forecast for Rosemont?
- Rosemont'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 Rosemont?
- See this week's day-by-day rain chances for Rosemont in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Rosemont?
- Current conditions for Rosemont and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Rosemont forecast updated?
- The Rosemont forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Rosemont?
- Today's sunrise and sunset times for Rosemont 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 Rosemont?
- The next few days in Rosemont's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Rosemont's warm-summer humid continental climate in Pennsylvania pairs 31°F Januarys with 77°F Julys, 46°F apart across the seasons.
Rosemont sees close to 43 inches of precipitation annually, falling across some 173 wet days.
At 40.0°N, Rosemont's 46°F summer-to-winter swing sets when Rosemont's gardens wake and when frost returns.
ZIP codes in Rosemont
- 19010