Watermelon in Ottawa: weekly temperatures and windows
Detailed weekly chart for this crop and place. For planting dates, see when to plant watermelon in Ottawa.
Growing window for Watermelon: May 31 – Aug 17 (79 days)
Planting window for Watermelon: May 31 – Jun 20 (21 days)
Usually too cold: Aug 17 – Dec 31
Outdoors: weekly temperatures and windows
Temperatures across the year for Ottawa. Shaded bands are this plant’s ideal and tolerable daytime air ranges. Growing is daytime air suitability; Planting is sow / plant-out conditions (same colour language). Window brackets mark each stretch.
- Ideal range
- Tolerable range
- Possible min to max
- Average min to max
- Suitable
- Tolerable
- Too cold
- Too hot
Selected week · tap a week or use the arrows
Week 22 · May 25 – May 31
Average 11 to 21 °C · Possible 3 to 34 °C
Growing: too cold
Planting: too cold
A week is in range when its average low and high sit inside the tolerance band 16 to 38 °C; it is suitable when that average range also overlaps the ideal 21 to 35 °C band and possible readings stay within 0 °C to 38 °C. Crossing a possible limit, or missing the ideal band, makes it tolerable; any chance of frost (possible low below 0 °C) makes it too cold. When a sowing window is calculated, weeks outside that window are uncoloured even if air is in range.
Based on average frost dates (35 seasons (1991–2025)).
- Ideal
- Tolerable
- Too cold
- Too hot
Show all 53 weeks
Cover method weekly charts
Outdoor weekly chart is above. Open a cover chart only if you grow under fleece, a cold frame, or an unheated greenhouse.
Dates for Ottawa use ERA5-Land cell 45.41, -75.70. How we calculated this · Algorithm 2026-10-season-10.