Your seasonal context
Understand the place before the date.
The 61479 area uses a representative location near 40.987°, -89.652°. In the nearby historical climate grid, July is the warmest month on average (24.1°C), while January is the coolest (-4.6°C). May has the highest mean daily precipitation (3.74 mm).
Monthly mean temperatures are below freezing in January, February, December. Outdoor planting during those months needs a separate protected-growing assessment. Use these seasonal differences to frame your questions for a local gardening adviser.
Light at your latitude
At 40.987° N, the length of the day changes independently of temperature. Compare the middle of three seasons when planning your garden.
Geometric daylight estimate from latitude and solar declination, rounded to 0.1 hour. This is time above a flat horizon, excluding atmospheric refraction, hills, buildings and cloud cover. It is not the direct-sun exposure of your bed. About solar-position calculations.
| Month | Mean air temperature | Mean precipitation / day |
|---|---|---|
| January | -4.6°C (24°F) | 1.58 mm |
| February | -2.9°C (27°F) | 1.74 mm |
| March | 3.8°C (39°F) | 2.11 mm |
| April | 10.7°C (51°F) | 3.24 mm |
| May | 16.7°C (62°F) | 3.74 mm |
| June | 21.9°C (71°F) | 3.65 mm |
| July | 24.1°C (75°F) | 3.10 mm |
| August | 23.2°C (74°F) | 3.14 mm |
| September | 19.2°C (66°F) | 2.89 mm |
| October | 11.5°C (53°F) | 2.67 mm |
| November | 4.5°C (40°F) | 1.99 mm |
| December | -1.8°C (29°F) | 1.84 mm |
NASA POWER regional grid, 0.5° latitude × 0.625° longitude. Grid center 41.000°, -89.375°. Monthly mean air temperature is neither a nightly low nor soil temperature. Rainfall averages do not set a watering schedule. Open the climate source.
Compare nearby places
Six nearby postal areas
Explore the closest listed postal areas by straight-line distance between their representative coordinates. A nearby garden may still have different soil, shelter or elevation.
| Postal area | Distance | Jan | Jul |
|---|---|---|---|
| Speer61479 · this area | — | -4.6°C | 24.1°C |
| EdelsteinIL 61526 | 7.2 km | -4.6°C | 24.1°C |
| Camp GroveIL 61424 | 10.2 km | -4.6°C | 24.1°C |
| PrincevilleIL 61559 | 13.3 km | -4.8°C | 24.2°C |
| WyomingIL 61491 | 13.3 km | -4.8°C | 24.2°C |
| CastletonIL 61426 | 15.3 km | -4.8°C | 24.2°C |
| ChillicotheIL 61523 | 15.5 km | -4.6°C | 24.1°C |
Distances use GeoNames representative postal coordinates, which may be estimated; they are not driving distances. Nearby areas often share one NASA POWER grid cell, so identical climate values are expected. Differences shown here describe the climate grids, not a measured difference between individual gardens.
What this postal area includes
Speer.
A ZIP area is a postal geography, not a neighborhood or municipal boundary. Place names may include multiple communities. The representative coordinates may be estimated. Nearby gardens can differ in elevation, shelter, slope and soil.
