Frost dates
Frost Dates by City
Average last spring frost, first fall frost, and frost-free growing-season length by city.
Garden climate data
Garden Climate Data for Frost Dates, Growing Degree Days and Crop Timing
Explore datasets for frost dates, growing degree days, crop heat requirements, city climate rankings, and short-season crop suitability. These pages are built as clear, linkable references for gardeners, writers, and researchers.
Core Garden Climate Datasets
These are the main reference datasets for season length, frost dates, seasonal heat, and crop timing.
Growing degree days
Growing Degree Days by City
Seasonal heat accumulation for comparing warm-season crop potential across locations.
Crop heat needs
Crop Heat Requirements
Typical crop GDD targets used to compare crop needs against local seasonal heat.
Maps and Visual Climate Explainers
These resources turn climate and crop-timing data into visual comparisons and plain-English explanations.
Climate atlas
Canada Garden Climate Atlas
Compare Canadian cities by frost-free days and base-50°F growing degree days using map-style views and regional summaries.
Climate atlas
U.S. Garden Climate Atlas
Compare U.S. cities by frost-free days and base-50°F growing degree days using map-style views and state summaries.
Visual explainer
Canada Long Season vs Warm Season Comparison
Learn why frost-free days measure time, growing degree days measure heat, and gardeners need both for warm-season crop planning.
City Climate Rankings
Compare cities by frost-free season length, seasonal heat, and other garden climate signals.
Short seasons
Cities With the Shortest Growing Seasons
Cities ranked by median frost-free windows.
428 items ranked.
Canada · Seasonal heat
Canadian Cities With the Highest Growing Degree Days
Canadian cities ranked by base 50°F growing degree day accumulation for warm-season crop planning.
178 items ranked.
Canada · Long seasons
Canadian Cities With the Longest Growing Seasons
Canadian cities ranked by median frost-free season length.
178 items ranked.
U.S. · Seasonal heat
US Cities With the Highest Growing Degree Days
U.S. cities ranked by base 50°F growing degree day accumulation for warm-season crop planning.
250 items ranked.
U.S. · Long seasons
US Cities With the Longest Growing Seasons
U.S. cities ranked by average frost-free growing season length.
250 items ranked.
Crop Suitability and Short-Season Risk
Compare crops by how demanding they are in cool, short, or timing-sensitive growing seasons.
Crop difficulty
Hardest Crops to Grow in Short Seasons
Crops ranked by how much timing pressure they create in short frost windows and lower-GDD locations.
24 items ranked.
Reliable crops
Most Forgiving Crops for Short-Season Gardeners
Crops ranked by how much practical timing margin they leave in short-season gardens.
24 items ranked.
Late planting risk
Crops That Lose the Most Margin When Planted Late
Crops ranked by how much heat and maturity margin they lose when planting slips by two weeks.
24 items ranked.
Late planting risk
Late Planting Penalty Chart
See which crops lose the most growing margin when planting slips by two weeks, and which are more forgiving.
Crop-Specific Climate Studies
These pages apply the same frost, heat, and crop-timing data to specific garden crops and crop-location combinations.
Watermelon
Best Canadian Cities for Growing Watermelon
Canadian cities ranked by how realistic outdoor watermelon is in a typical outdoor season.
428 items ranked.
Tomatoes
Best Canadian Cities for Growing Tomatoes
Canadian cities ranked by outdoor tomato suitability, seasonal heat, and crop timing margin.
178 items ranked.
Peppers
Best Canadian Cities for Growing Peppers
Canadian cities ranked by outdoor pepper suitability, timing sensitivity, and seasonal heat.
428 items ranked.
How the data works
Data Sources and Methodology
Learn how GrowByDate turns frost dates, growing degree days, crop heat requirements, and planting windows into garden planning guidance.
GrowByDate combines public climate normals, frost-date estimates, growing degree day calculations, and crop maturity assumptions to create garden-focused planning datasets. The rankings and comparison pages are derived from those underlying climate and crop-timing signals.
- Climate records and normals are used to estimate typical seasonal conditions such as frost timing and heat accumulation.
- Growing degree days estimate usable seasonal warmth in a way that is more crop-relevant than calendar days alone.
- Crop maturity assumptions help compare crop heat needs against local frost windows and seasonal heat.
- Derived GrowByDate metrics translate the reference data into rankings for city climate, crop difficulty, late planting risk, and crop-location suitability.
These datasets are for long-term planning and comparison, not short-term weather forecasting. Averages cannot capture every slope, cold pocket, raised bed, windy site, urban heat island, lake effect, soil condition, irrigation pattern, pest issue, or variety difference. Use the data to make better starting decisions, then adjust with local forecasts and what you know about your own garden.