Today
Sun, Jun 21
Overcast
22°14°
- Rain chance
- 26%
- Precip
- 0 mm
- Max wind
- 16 km/h
Cornwall weather forecast
Ontario, Canada · Toronto time · 45.02°, -74.73°
Current conditions · 9:00 AM local
Current conditions in Cornwall
18°C
Overcast
Feels like 18°C
- Humidity
- 87%
- Wind
- 13 km/h WSW
- Gusts
- 23 km/h
- UV index
- 0.35
- Visibility
- 15.7 km
Right now
Cornwall is currently seeing overcast, with 18 °C on the thermometer. It feels close to the actual reading at 18 °C. Wind is from the WSW at 13 km/h. Humidity stands at 87% with sea-level pressure near 1011 hPa.
At a glance
Today
22° / 14°Overcast
Tomorrow
24° / 13°Slight rain · 45% chance of rain
Upcoming · to Saturday
25° / 11°Highs 25°, lows 11°. The most active day looks like Friday, when rain chances peak at 73%.
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Next 3 days
Expect overcast today, between 14 °C and 22 °C. Expect slight rain tomorrow, between 13 °C and 24 °C. Rain chance peaks at 45% with around 4 mm possible. Expect light drizzle Tuesday, between 13 °C and 23 °C.
Tomorrow
Mon, Jun 22
Slight rain
24°13°
- Rain chance
- 45%
- Precip
- 4 mm
- Max wind
- 23 km/h
Tuesday
Tue, Jun 23
Light drizzle
23°13°
- Rain chance
- 12%
- Precip
- 0.3 mm
- Max wind
- 16 km/h
Next 48 hours
- 12 AM16°9%5 km/h
- 1 AM15°19%7 km/h
- 2 AM15°20%10 km/h
- 3 AM15°18%9 km/h
- 4 AM15°23%6 km/h
- 5 AM14°25%6 km/h
- 6 AM14°20%7 km/h
- 7 AM15°22%12 km/h
- 8 AM17°25%11 km/h
- 9 AM18°26%13 km/h
- 10 AM18°23%13 km/h
- 11 AM19°24%16 km/h
- 12 PM20°15%14 km/h
- 1 PM20°14%12 km/h
- 2 PM21°13%13 km/h
- 3 PM21°12%15 km/h
- 4 PM22°8%14 km/h
- 5 PM21°7%10 km/h
- 6 PM21°6%11 km/h
- 7 PM20°7%8 km/h
- 8 PM19°9%5 km/h
- 9 PM18°4%7 km/h
- 10 PM17°4%7 km/h
- 11 PM16°2%8 km/h
- 12 AM16°1%7 km/h
- 1 AM15°1%7 km/h
- 2 AM14°1%6 km/h
- 3 AM14°1%6 km/h
- 4 AM13°0%8 km/h
- 5 AM13°0%6 km/h
- 6 AM13°0%5 km/h
- 7 AM15°0%4 km/h
- 8 AM16°0%3 km/h
- 9 AM18°0%4 km/h
- 10 AM20°1%3 km/h
- 11 AM22°1%3 km/h
- 12 PM22°3%2 km/h
- 1 PM23°9%2 km/h
- 2 PM24°19%5 km/h
- 3 PM19°25%23 km/h
- 4 PM20°30%12 km/h
- 5 PM19°33%10 km/h
- 6 PM18°45%7 km/h
- 7 PM18°40%8 km/h
- 8 PM17°32%10 km/h
- 9 PM16°12%10 km/h
- 10 PM16°12%9 km/h
- 11 PM16°12%11 km/h
In depth
The weather picture for Cornwall opens with overcast; it's 18 °C out, feeling like 18 °C. Today's forecast calls for overcast, topping out near 22 °C before falling back to 14 °C overnight. Winds blow mainly from the WSW around 16 km/h, with gusts up to 24 km/h. Daytime highs hold fairly steady this week, staying within 22 to 25 °C. Rain is in the picture on tomorrow, Thursday, Friday, with roughly 18 mm expected in total across the week. Tomorrow brings slight rain with a high of 24 °C and a 45% chance of precipitation. Sunrise comes at 05:12 and sunset at 20:49, giving 15.6 hours of daylight. Current humidity sits at 87% with pressure near 1011 hPa. Looking further out, Thursday shows moderate rain showers with a high around 25 °C, while Saturday ends the week at 23 °C. Forecast details are refreshed throughout the day as new model runs arrive, so check back for the latest figures.
Air quality
30
Good
US AQI · European AQI 18
Air quality in Cornwall is currently good, with a US AQI of 30 (European AQI 18). The dominant pollutant right now is ozone. Air quality is healthy; no precautions needed. Fine particulate matter (PM2.5) measures 5.5 µg/m³.
Pollutants
- PM2.5
- 5.5 µg/m³
- PM10
- 5.7 µg/m³
- Ozone (O₃)
- 45 µg/m³
- NO₂
- 2.1 µg/m³
- SO₂
- 0.7 µg/m³
- CO
- 108 µg/m³
- Dust
- 0 µg/m³
Sun & UV
- Sunrise
- 5:12 AM
- Sunset
- 8:49 PM
- Daylight
- 15h 37m
- Max UV
- 4.4 Moderate
Wind
- Wind
- 13 km/h
- Gusts
- 23 km/h
- Direction
- WSW (247°)
Farming weather
Soil temperatures today read surface 17.4 °C, 6 cm 17.5 °C, 18 cm 17.5 °C, 54 cm 15.2 °C. Soil moisture sits at 0-1 cm at 0.32 m³/m³, 3-9 cm at 0.32 m³/m³, 27-81 cm at 0.36 m³/m³. For wheat, the root-zone reading is within the ideal 0.2-0.35 m³/m³ band. ET0 of 26 mm modestly outpaces the 18 mm of forecast rain; light supplemental irrigation may help. A suitable spraying window opens around 06:00 on 2026-06-21, with winds at or below 15 km/h and no rain expected. Projected growing degree days over the next week: wheat 94, maize 56.
- Topsoil moisture
- 0.335 m³/m³
- Soil temp
- 17°C
- ET₀ today
- 3.15 mm
- Spray window
- ~5:00
- Rain (next 7d)
- 18.3 mm
- Wind
- 13 km/h
- Humidity
- 87%
Advisory summary
No weather alert thresholds are crossed for Cornwall in the current forecast (derived from forecast data, not official warnings). Conditions may still change — check back for updates.
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All data for Cornwall
| Variable | Value |
|---|---|
| City | Cornwall, Ontario, Canada |
| Coordinates | 45.01809, -74.72815 |
| Elevation | 59 m |
| Timezone | America/Toronto |
| Population | 48,821 |
| Observed at (local) | 9:00 AM |
| Temperature (2 m) | 18°C |
| Apparent temperature | 18°C |
| Relative humidity (2 m) | 87% |
| Dew point (2 m) | 15°C |
| Precipitation (last hour) | 0 mm |
| Rain | 0 mm |
| Showers | 0 mm |
| Snowfall | 0 cm |
| Weather code (WMO) | 3 |
| Cloud cover | 100% |
| Surface pressure | 1004 hPa |
| Sea-level pressure | 1011 hPa |
| Wind speed (10 m) | 13 km/h |
| Wind gusts (10 m) | 23 km/h |
| Wind direction (10 m) | 247° (WSW) |
| Visibility | 15.7 km |
| UV index | 0.35 |
| Day / night | Day |
| Today max / min | 22°C / 14°C |
| Today feels-like max / min | 22°C / 14°C |
| Today precipitation sum | 0 mm |
| Today rain sum | 0 mm |
| Today snowfall sum | 0 cm |
| Today max precip probability | 26% |
| Today max wind / gusts | 16 km/h / 24 km/h |
| Dominant wind direction | 241° (WSW) |
| Sunrise / sunset | 5:12 AM / 8:49 PM |
| Daylight duration | 15h 37m |
| Sunshine duration | 6h 39m |
| Max UV index | 4.4 |
| Reference evapotranspiration (ET₀) | 3.15 mm |
| Topsoil moisture (0–1 cm) | 0.335 m³/m³ |
| Surface soil temperature | 17°C |
| US AQI | 30 |
| European AQI | 18 |
| PM2.5 | 5.5 µg/m³ |
| PM10 | 5.7 µg/m³ |
| Ozone (O₃) | 45 µg/m³ |
| Nitrogen dioxide (NO₂) | 2.1 µg/m³ |
| Sulphur dioxide (SO₂) | 0.7 µg/m³ |
| Carbon monoxide (CO) | 108 µg/m³ |
| Dust | 0 µg/m³ |
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<iframe src="https://weathertomorrow.cloud/embed/city/ca/ontario/cornwall" width="320" height="180" frameborder="0" title="Cornwall weather" loading="lazy"></iframe>Frequently asked questions
Will it rain in Cornwall tomorrow?
There is a moderate chance of rain in Cornwall tomorrow, peaking at 45%.
What is the temperature in Cornwall today?
Today Cornwall sees overcast with a high of 22 °C and a low of 14 °C.
How hot will it be in Cornwall tomorrow?
Tomorrow's high in Cornwall is forecast at 24 °C with slight rain.
Is it windy in Cornwall today?
No, not especially; gusts only reach up to 24 km/h today.
What is the UV index in Cornwall today?
The UV index peaks at 4 today, which is moderate.
What time is sunrise and sunset in Cornwall today?
The sun rises at 05:12 and sets at 20:49 local time.
Is the air quality in Cornwall good today?
Air quality is good right now, with a US AQI reading of 30.