Trenton, New Jersey Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Trenton weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——89°56°—
- FridayJun 5Overcast——95°63°+6°
- SaturdayJun 6Overcast28%—91°69°-4°
- SundayJun 7Drizzle38%—88°68°-3°
- MondayJun 8Overcast17%—79°62°-9°
- TuesdayJun 9Overcast——87°59°+8°
- WednesdayJun 10Overcast10%—90°63°+3°
PM2.5 at 10.2 µg/m³ (AQI 53) with a 0.91 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust. AQI down 11 over the last 6 hours (steady decline since this morning).
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 31 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 14 by mid-afternoon.
- Present
- AQI 31
- UV peak
- 3.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 14
PM × Wind × Precip
PM2.5 at 10.2 µg/m³ (AQI 53) with a 0.91 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.91
- Wind
- calm
- 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).
A summer fog for fair, a winter fog for rain.
- Moonrise
- 3:27 AM
- Moonset
- 12:58 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Trenton at a glance
- Today vs. normal: 16°F below the seasonal normal for this latitude
- Last frost: April 17 (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
July brings Trenton's highest temperatures, averaging around 76°F, while January delivers the coldest conditions at roughly 31°F. Precipitation follows a different pattern, with July receiving the most rainfall at 4.8 inches and February seeing the least at 2.8 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 31° | 3.6″ | 7 |
| February | 33° | 2.8″ | 5 |
| March | 41° | 4.4″ | 8 |
| April | 52° | 3.6″ | 7 |
| May | 61° | 3.5″ | 7 |
| June | 71° | 4.7″ | 7 |
| July | 76° | 4.8″ | 6 |
| August | 74° | 4.3″ | 6 |
| September | 67° | 4.1″ | 7 |
| October | 55° | 4.0″ | 5 |
| November | 45° | 3.2″ | 6 |
| December | 35° | 4.3″ | 7 |
Regional context
The city falls within a warm-summer humid continental climate region, sharing temperature ranges, seasonal patterns, and growing conditions with other nearby cities in this climate zone.
Similar climates: Newark, NJ, Jersey City, NJ, Paterson, NJ, Elizabeth, NJ, Clifton, NJ.
Naturalist notes
Late May brings the arrival of migrating warblers to Trenton's parks and wooded areas, their songs filling the canopy as they search for insects among newly emerged leaves.
Cherry blossoms typically reach peak bloom in mid-April, coinciding with the last expected frost dates in the region.
Frequently asked
- When does it freeze in Trenton?
- The last spring frost in Trenton typically occurs around mid-April, while the first fall frost usually arrives around mid-November.
- What is the rainy season in Trenton?
- July receives the most rainfall, averaging about 4.8 inches, while the city's total annual precipitation reaches roughly 47 inches.
- What is the warmest month in Trenton?
- July typically records the highest temperatures, with averages around 76°F.
- What is the coldest month in Trenton?
- January brings the coldest temperatures, averaging about 31°F.
- When can I start a vegetable garden in Trenton?
- 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 Trenton get?
- The city experiences about 76 rainy days per year on average.
- What hardiness zone is Trenton?
- Trenton's USDA hardiness zone depends on its lowest average winter temperature; the USDA's online lookup tool can provide the current zone designation using the city ZIP code.
Climate
Trenton, New Jersey experiences a warm-summer humid continental climate. January temperatures typically hover near 31°F, while July averages reach 76°F, creating a 45°F seasonal swing.
Annual precipitation totals about 47 inches, distributed across roughly 76 rainy days throughout the year.
Location at 40.2°N latitude, along with proximity to large water bodies and local elevation, determines the rhythms of plant growth, frost timing, and daily weather patterns.