Longmont, CO Weather & Growing Conditions
Today
74°F
Slight Chance Rain Showers then Chance Showers And Thunderstorms
A slight chance of rain showers between 9am and noon, then a chance of showers and thunderstorms between noon and 3pm, then showers and thunderstorms likely. Partly sunny. High near 74, with temperatures falling to around 67 in the afternoon. South southeast wind 1 to 6 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 74°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 1 to 6 mph SSE | 58% |
| Tonight | 49°F | Chance Showers And Thunderstorms then Partly Cloudy | 5 mph WNW | 31% |
| Sunday | 70°F | Partly Sunny then Chance Showers And Thunderstorms | 3 mph NE | 29% |
| Sunday Night | 48°F | Chance Showers And Thunderstorms then Partly Cloudy | 0 to 3 mph NNW | 28% |
| Monday | 71°F | Sunny | 0 to 5 mph E | 4% |
| Monday Night | 50°F | Partly Cloudy | 1 to 5 mph NNW | 11% |
| Tuesday | 75°F | Mostly Sunny | 0 to 3 mph NE | 11% |
| Tuesday Night | 51°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 mph NW | 18% |
| Wednesday | 76°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 0 to 3 mph NE | 17% |
| Wednesday Night | 51°F | Partly Cloudy | 5 mph NW | 12% |
| Thursday | 78°F | Mostly Sunny | 2 to 6 mph SSE | 8% |
| Thursday Night | 53°F | Partly Cloudy | 0 to 3 mph SW | 11% |
| Friday | 78°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 0 to 5 mph E | 16% |
| Friday Night | 53°F | Slight Chance Rain Showers then Partly Cloudy | 3 mph SW | 18% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Longmont, CO
Last spring frost
May 7
First fall frost
Oct 5
Growing season
151 days
Hardiness zone
6a
Explore more for Longmont, CO: full frost dates · planting calendar · Colorado frost dates
Climate data from the nearest NOAA station, Longmont 2 Ese, Co (7 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.