Weather in Derby, Colorado
High country wildflowers peak. Day 58 of spring. Read this microseason across nine climate regions →
- TodayMay 16Overcast14%79°55°
- SundayMay 17Drizzle37%70°53°
- MondayMay 18Heavy Snow Shwrs99%51°33°
- TuesdayMay 19Drizzle79%47°30°
- WednesdayMay 20Overcast79%68°39°
- ThursdayMay 21Drizzle39%57°45°
- FridayMay 22Overcast29%71°43°
- PM 2.5
- 5.8 μg/m³
- PM 10
- 9.1 μg/m³
- NO₂
- 2.1 μg/m³
- Ozone
- 133.0 μg/m³
- UV Index
- 1.4 Low
Flowers blooming in late autumn, a sure sign of a bad winter coming.
- Moonrise
- 11:07 AM
- Moonset
- 1:23 AM
- In sign
- ♉︎ Taurus
High country wildflowers peak
Derby at a glance
- Today vs. normal: 7°F above the seasonal normal for this latitude
- Last frost: April 15 (climatological average for this latitude)
- Microseason: 28 of 72, May 16–20
- Planting window: Direct sow okra, melons, and southern peas. Thin carrot rows.
Right now in the garden
Warm-season window is open
As of May 16, 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.
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
Derby's warmest month is July (~75°F mean) and its coldest is December (~32°F). Rainfall peaks in May (2.3 inches) and bottoms out in January (0.5 inches).
| Month | Mean temp | Precip | Rainy days |
|---|---|---|---|
| January | 32° | 0.5″ | 2 |
| February | 33° | 0.5″ | 2 |
| March | 42° | 1.1″ | 3 |
| April | 48° | 1.7″ | 4 |
| May | 58° | 2.3″ | 5 |
| June | 69° | 1.7″ | 4 |
| July | 75° | 2.1″ | 4 |
| August | 73° | 1.8″ | 4 |
| September | 64° | 1.5″ | 3 |
| October | 51° | 1.0″ | 3 |
| November | 40° | 0.7″ | 2 |
| December | 32° | 0.5″ | 2 |
Regional context
Derby sits within a hot desert climate region — a cohort that shares similar temperature ranges, seasonal patterns, and growing conditions across nearby cities.
Similar climates: Denver, CO, Colorado Springs, CO, Aurora, CO, Lakewood, CO, Thornton, CO.
Frequently asked
- When does it freeze in Derby?
- Derby's last spring frost typically falls around mid-April, and the first fall frost arrives around mid-November.
- What is the rainy season in Derby?
- May is the wettest month with about 2.3 inches of rain on average; the city receives roughly 15 inches annually.
- What is the warmest month in Derby?
- July is typically warmest, averaging about 75°F.
- What is the coldest month in Derby?
- December is typically coldest, averaging about 32°F.
- When can I start a vegetable garden in Derby?
- 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 Derby get?
- Derby averages about 38 rainy days per year.
- What hardiness zone is Derby?
- Derby'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
Derby, Colorado sits in a hot desert climate zone. January means hover near 32°F while July averages 75°F — a 43°F seasonal swing.
Across the year, Derby receives about 15 inches of precipitation spread over roughly 38 rainy days.
The rhythm of the year is set by latitude (39.8°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.