Derby, Connecticut Weather
Honeysuckle sweetens the night. Day 90 of spring. Read this microseason across nine climate regions →
Derby weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 17Overcast——78°58°—
- ThursdayJun 18Rain47%0.13″85°63°+7°
- FridayJun 19Overcast——86°62°+1°
- SaturdayJun 20Overcast——82°59°-4°
- SundayJun 21Light Drizzle—0.01″82°55°0°
- MondayJun 22Rain55%0.61″73°60°-9°
- TuesdayJun 23Mostly Clear38%—80°53°+7°
AQI 28 (Good), driven by PM2.5. AQI down 14 over the last 6 hours (gradual decline). PM2.5 at 16.4 µg/m³ (AQI 65) with a 0.85 fine-to-coarse ratio and 3 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 during the projected peak around 5 PM.
What's driving it
PM × Wind × Precip
PM2.5 at 16.4 µg/m³ (AQI 65) with a 0.85 fine-to-coarse ratio and 3 mph wind — combustion smoke trapped in calm air, not road dust.
- PM2.5/PM10
- 0.85
- 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
- 7:45 AM
- Moonset
- 10:32 PM
- In sign
- ♋︎ Cancer
Honeysuckle sweetens the night
Derby at a glance
- Today vs. normal: 12°F below the seasonal normal for this latitude
- Last frost: April 24 (climatological average for this latitude)
- Microseason: Jun 16–20
- Planting window: Stake and prune tomato suckers. Watch for squash vine borers.
15-Day Forecast — Derby
- Wed78°58°7%
- Thu85°63°47%
- Fri86°62°3%
- Sat82°59°2%
- Sun82°55°8%
- Mon73°60°55%
- Tue80°53°38%
- Wed78°59°8%
- Thu82°58°15%
- Fri85°63°25%
- Sat92°65°20%
- Sun100°69°30%
- Mon84°68°36%
- Tue83°71°39%
- Wed88°69°44%
Forecast data from Open-Meteo (CC BY 4.0).
Right now in the garden
Peak growing season
As of June 17, 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 — Derby
SPC has placed Derby in the Slight Risk category for severe thunderstorms tomorrow.
- TODAYNONENo severe risk
- TOMORROWSLGTSlight Risk
- DAY 3NONENo severe risk
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 · June 16–20
Honeysuckle sweetens the night
Japanese honeysuckle perfumes parks after dark.
Day 168 of 365 · Wedge 34 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
July is Derby's warmest stretch (~75°F) and January its coldest (~30°F); precipitation crests in December at 4.7 inches and ebbs in February to 3.3 inches.
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 30° | 4.0″ | 14 |
| February | 32° | 3.3″ | 14 |
| March | 39° | 3.9″ | 16 |
| April | 50° | 4.3″ | 18 |
| May | 58° | 4.0″ | 19 |
| June | 68° | 3.9″ | 18 |
| July | 75° | 3.6″ | 18 |
| August | 74° | 4.0″ | 17 |
| September | 68° | 3.7″ | 14 |
| October | 58° | 3.7″ | 13 |
| November | 45° | 4.6″ | 14 |
| December | 35° | 4.7″ | 14 |
Regional context
Per NOAA NCEI 1991-2020 normals, Derby runs from a 30°F January mean to 75°F in July, a 45°F seasonal spread, with near 47.7 inches of precipitation across about 188 wet days.
No season owns Derby's rain: December reaches 4.7 inches across 13.9 days and February keeps 3.3 inches on 13.5, an even spread through Derby's year. It is a balanced pattern Derby shares with places like Ansonia, CT, Shelton, CT and Oronoque, CT.
Around mid-April, Derby sheds its freezing nights — peas, lettuce, spinach, and radishes go into Derby's beds. Derby's heat-lovers — tomatoes, peppers, squash — hold off until Derby's frost risk clears, 10-14 days on. By mid-November, frost is back in Derby — protect or harvest anything tender. A creek-bottom lot in Derby can lag Derby's last frost 7-10 days behind a south slope.
Similar climates: Ansonia, CT, Shelton, CT, Oronoque, CT, East Village, CT, Daniels Farm, CT.
Frequently asked
- When does it freeze in Derby?
- Derby's last spring frost lands near mid-April, and in Derby the first fall frost follows around mid-November.
- What is the rainy season in Derby?
- Rainfall in Derby peaks in December near 4.7 inches, out of about 48 inches annually.
- What is the warmest month in Derby?
- On average July tops the year in Derby at about 75°F.
- What is the coldest month in Derby?
- The coldest stretch in Derby falls in January, around 30°F on average.
- When can I start a vegetable garden in Derby?
- In Derby, sow peas and hardy greens around mid-April; Derby's tomatoes and peppers wait two weeks more.
- How many rainy days does Derby get?
- Derby records around 188 days of measurable precipitation annually.
- What hardiness zone is Derby?
- With January around 30°F, Derby's zone reflects that minimum — the USDA ZIP map confirms Derby's band.
- What is the 10-day forecast for Derby?
- Derby'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 Derby?
- See this week's day-by-day rain chances for Derby in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Derby?
- Current conditions for Derby and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Derby forecast updated?
- The Derby forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Derby?
- Day length in Derby peaks around the June solstice — earliest sunrise and latest sunset — and is shortest near the December solstice.
- How accurate is the weather forecast for Derby?
- The next few days in Derby's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Climate
Set in a warm-summer humid continental zone, Derby, Connecticut swings from 30°F in the heart of winter to 75°F at midsummer — a 45°F arc.
Across the year, Derby collects about 48 inches of precipitation over roughly 188 days with measurable rain or snow.
Derby sits at 41.3°N; that 45°F seasonal swing frames planting windows and frost dates across Derby.
ZIP codes in Derby
- 06418