Caldwell, New Jersey Weather
Fireflies rise from the lawn. Day 77 of spring. Read this microseason across nine climate regions →
Caldwell weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 4Overcast——87°59°—
- FridayJun 5Overcast——92°65°+5°
- SaturdayJun 6Heavy Drizzle45%—91°67°-1°
- SundayJun 7Drizzle45%0.02″87°66°-4°
- MondayJun 8Overcast13%—80°61°-7°
- TuesdayJun 9Overcast——85°59°+5°
- WednesdayJun 10Partly Cloudy11%—89°63°+4°
PM2.5 at 13.3 µg/m³ (AQI 59) with a 0.95 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust. AQI down 16 over the last 6 hours — air quality is improving sharply.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
PM × Wind × Precip
PM2.5 at 13.3 µg/m³ (AQI 59) with a 0.95 fine-to-coarse ratio and 4 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.95
- 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
- 12:54 PM
- In sign
- ♑︎ Capricorn
Fireflies rise from the lawn
Caldwell at a glance
- Today vs. normal: 15°F below the seasonal normal for this latitude
- Last frost: April 21 (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 — Caldwell
SPC has placed Caldwell in the General Thunderstorms category for severe thunderstorms day after tomorrow.
- TODAYNONENo severe risk
- TOMORROWNONENo severe risk
- DAY 3TSTMGeneral Thunderstorms
Thunderstorms possible. Not severe, but capable of producing lightning and brief heavy rain.
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
Caldwell's warmest month is July (~78°F mean) and its coldest is January (~32°F). Rainfall peaks in June (4.9 inches) and bottoms out in February (3.3 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 32° | 3.7″ | 7 |
| February | 34° | 3.3″ | 6 |
| March | 41° | 4.3″ | 7 |
| April | 52° | 4.1″ | 7 |
| May | 63° | 4.4″ | 8 |
| June | 72° | 4.9″ | 7 |
| July | 78° | 4.8″ | 6 |
| August | 76° | 4.4″ | 7 |
| September | 69° | 4.3″ | 6 |
| October | 57° | 4.2″ | 6 |
| November | 46° | 3.6″ | 6 |
| December | 37° | 4.6″ | 8 |
Regional context
Caldwell 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: Trenton, NJ, Newark, NJ, Jersey City, NJ, Paterson, NJ, Elizabeth, NJ.
Frequently asked
- When does it freeze in Caldwell?
- Caldwell's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Caldwell?
- June is the wettest month with about 4.9 inches of rain on average; the city receives roughly 50 inches annually.
- What is the warmest month in Caldwell?
- July is typically warmest, averaging about 78°F.
- What is the coldest month in Caldwell?
- January is typically coldest, averaging about 32°F.
- When can I start a vegetable garden in Caldwell?
- 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 Caldwell get?
- Caldwell averages about 79 rainy days per year.
- What hardiness zone is Caldwell?
- Caldwell'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
Caldwell, New Jersey sits in a warm-summer humid continental climate zone. January means hover near 32°F while July averages 78°F — a 46°F seasonal swing.
Across the year, Caldwell receives about 50 inches of precipitation spread over roughly 79 rainy days.
The rhythm of the year is set by latitude (40.8°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.
Beaches near Caldwell
- Jacob Riis Beach28.1 mi
- Rockaway Beach Beach29.2 mi
Each linked page shows live water temperature, wave height, swim and surf verdicts, tides, and rip-current risk from NDBC + NOAA + NWS data.