Your seasonal context
Understand the place before the date.
How local is this information?
- Postal precision
- Estimated postal coordinates · limited location precision
- Climate reference
- ECCC · 1991–2020 · 3.0 km from the postal reference point
- Planting dates
- General crop stages · choose a locally advised date
- Source review
- September 28, 2026 · source data period is separate
Distance alone does not establish a climate match. Elevation, coastal exposure, urban shelter and soil can differ; the postal location has no verified garden elevation.
The postal reference point is near 43.923°, -78.868°. At the nearest qualifying ECCC station reference (OSHAWA), July is the warmest month on average (20.9°C), while January is the coolest (-5.0°C). This does not measure your garden’s temperature.
Reference monthly means are below freezing in January, February, December. This signals a need to assess protected growing, not a calculated planting prohibition. Tomatoes are frost sensitive: check local frost guidance, soil conditions and the remaining growing season. A monthly average cannot identify a safe planting day.
Light at your latitude
At 43.923° 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 | Monthly precipitation total |
|---|---|---|
| January | -5.0°C (23°F) | 74.7 mm |
| February | -4.2°C (24°F) | 53.5 mm |
| March | 0.3°C (33°F) | 53.9 mm |
| April | 6.2°C (43°F) | 86.9 mm |
| May | 12.6°C (55°F) | 85.1 mm |
| June | 17.8°C (64°F) | 94.0 mm |
| July | 20.9°C (70°F) | 85.8 mm |
| August | 20.1°C (68°F) | 74.2 mm |
| September | 16.2°C (61°F) | 86.2 mm |
| October | 9.5°C (49°F) | 71.8 mm |
| November | 3.9°C (39°F) | 72.5 mm |
| December | -1.2°C (30°F) | 67.8 mm |
Historical station normals are not current weather or a last-frost prediction. Station elevation: 112 m. Temperature coverage code: C. Precipitation coverage code: C. Monthly totals are not daily rainfall or a watering schedule. This composite joins station records; representative metadata coordinates span up to 6.8 km. Open official station data.
Compare NASA regional grid context · 2001–2020
| Month | Mean air temperature | Mean precipitation / day |
|---|---|---|
| January | -5.9°C (21°F) | 1.67 mm |
| February | -5.7°C (22°F) | 1.67 mm |
| March | -0.9°C (30°F) | 1.66 mm |
| April | 5.2°C (41°F) | 2.26 mm |
| May | 11.9°C (53°F) | 2.13 mm |
| June | 18.0°C (64°F) | 2.18 mm |
| July | 22.0°C (72°F) | 2.16 mm |
| August | 21.5°C (71°F) | 1.75 mm |
| September | 17.5°C (64°F) | 1.96 mm |
| October | 10.0°C (50°F) | 2.16 mm |
| November | 3.4°C (38°F) | 2.04 mm |
| December | -2.4°C (28°F) | 1.99 mm |
NASA POWER regional grid, 0.5° latitude × 0.625° longitude. Grid center 44.000°, -78.750°. 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
Tomatoes around L1G
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 |
|---|---|---|---|
| Oshawa CentralL1G · this area | — | -5.9°C | 22.0°C |
| Oshawa EastON L1K | 3.2 km | -5.9°C | 22.0°C |
| Oshawa SouthwestON L1J | 4.3 km | -5.9°C | 22.0°C |
| Oshawa NorthON L1L | 4.5 km | -5.9°C | 22.0°C |
| Oshawa SoutheastON L1H | 5.6 km | -5.9°C | 22.0°C |
| Whitby CentralON L1R | 5.8 km | -5.9°C | 22.0°C |
| Whitby SoutheastON L1N | 7.4 km | -5.9°C | 22.0°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.
Regional advice
Choose a local planting window.
Local volunteer gardening groups; Ontario does not have one province-wide planting day.
Ask which dates refer to indoor seed starting, direct sowing or transplanting, and whether they cover spring or fall. This referral is not a verified postal-code planting calendar.
Find an official community climate stationThe growing checklist
Give tomatoes a considered start.
Check the root ball while the plant settles in. Keep moisture consistent without leaving the roots in saturated soil, and put supports in place while plants are small.
- Start seed indoors. Start early enough to raise a transplant before the locally recommended outdoor planting window. Indoor sowing and outdoor planting are separate dates.
- Harden off and transplant. Acclimate seedlings gradually. Set plants outside only when local frost risk, night temperatures and soil conditions suit this crop.
- Plan a fall crop separately. Check a local fall schedule and the variety’s maturity time. A spring start date is not a fall planting recommendation.
Inspect soil moisture and drainage in the actual bed; rainfall normals cannot tell you whether roots need water today.
These are general growing stages, not local planting dates. Minnesota calendar dates are not transferred to other regions. Read the Extension guide to growing stages.
One small next step
Make a date to check your garden.
Choose your own reminder date after checking local advice. This is a personal planning prompt, not a calculated planting recommendation.
An .ics file works with Apple Calendar, Google Calendar and Outlook. Your chosen date stays in your browser until you download it.
What this postal area includes
Oshawa Central.
A Canadian forward sortation area is the first three characters of a postal code. It can cover several communities, especially outside cities. The representative coordinates may be estimated. Nearby gardens can differ in elevation, shelter, slope and soil.
