New Castle, Colorado Weather
Pikas hayfeeding in granite peaks. Day 78 of spring. Read this microseason across nine climate regions →
New Castle weather forecast — hour by hour, 7-day outlook, NOAA radar
- TodayJun 5Overcast——90°61°—
- SaturdayJun 6Overcast——90°66°0°
- SundayJun 7Overcast——84°54°-6°
- MondayJun 8Overcast——85°50°+1°
- TuesdayJun 9Overcast——88°52°+3°
- WednesdayJun 10Partly Cloudy10%—86°48°-2°
- ThursdayJun 11Partly Cloudy——77°41°-9°
AQI 50 (Good), driven by Ozone. AQI down 27 over the last 6 hours — air quality is improving sharply. Ozone at AQI 42 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 19 by mid-afternoon.
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 42 now. With UV 3.3 peaking around 1 PM under clear skies, surface ozone likely climbs to AQI 19 by mid-afternoon.
- Present
- AQI 42
- UV peak
- 3.3 at 1 PM
- Sky at peak
- clear
- Projected peak
- AQI 19
PM × Wind × Precip
PM2.5/PM10 ratio 0.55 with 6 mph wind — characteristic of long-range haze transport rather than a local source.
- PM2.5/PM10
- 0.55
- Wind
- light
- Recent rain
- 0h in last 6h
- Pattern
- transport
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).
The higher the clouds, the finer the weather.
- Moonrise
- 6:11 AM
- Moonset
- 4:21 PM
- In sign
- ♒︎ Aquarius
Pikas hayfeeding in granite peaks
New Castle at a glance
- Today vs. normal: 11°F below the seasonal normal for this latitude
- Last frost: April 13 (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
Warm-season window is open
As of June 5, the last spring frost has passed for most years. Transplant tomatoes, peppers, eggplants, basil, and cucurbits (cucumbers, squash, melons) now. Direct-sow beans and corn into warm soil.
SPC Convective Outlook
Storm Prediction Center — New Castle
SPC has placed New Castle in the General Thunderstorms category for severe thunderstorms tomorrow.
- TODAYNONENo severe risk
- TOMORROWTSTMGeneral Thunderstorms
- DAY 3NONENo severe risk
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.