Cool, clear Sunday before a brief warm-up
Newmarket is starting Sunday under sunny skies, with the temperature at 16.5 C as of mid-morning and a light northwesterly wind near 8 km/h. Air pressure is 101.6 kPa and rising, humidity sits around 65%, and the dew point is 9.9 C, indicating a dry, comfortable feel to the air. The afternoon high is expected to reach 22 C, which is below the seasonal norm of 26 C for this time of July.
Environment Canada’s outlook points to a clear, crisp night with a low near 10 C, also cooler than the typical overnight 15 C. Winds from the north are forecast to ease by midday, keeping conditions stable for outdoor plans, whether that’s a park visit, yard work or local travel.
“Sunny. Wind north 20 km/h becoming light this morning. High 22. UV index 7 or high.”
Heat returns Monday; showers likely Tuesday
After Sunday’s moderate temperatures, Monday is set to rebound to a daytime high near 26 C, with a humidex of 29 and a very high UV index of 8. A southerly breeze around 20 km/h is expected later in the afternoon. Cloud periods move in Monday night, bringing a 40% chance of showers and a low near 18 C.
On Tuesday, forecasters call for a cooler, unsettled day with a 60% chance of showers and a high near 21 C. The chance of precipitation tapers Tuesday night to 30% with a low around 12 C. Wednesday remains mostly cloudy with a daytime high close to 19 C, before sunnier, seasonable weather returns late week.
Late-week trend: back to seasonal
From Thursday onward, the outlook improves. Thursday is expected to be sunny and 23 C, followed by a mix of sun and cloud Friday near 24 C. Cloudier periods Friday night carry a 60% chance of showers. Saturday holds a 30% chance of showers with highs around 24 C, close to normal for mid-July. Sunrise today was at 5:52 a.m. and sunset is at 8:56 p.m.
What this means for your day
With cooler-than-average air and lower humidity Sunday, air quality and outdoor comfort are favourable. The higher sun angle still drives UV exposure, however, so protection remains important through the afternoon. The early-week warm-up, followed by showers, could influence commuting and outdoor work schedules on Tuesday, as well as lawn watering and recreation planning.
- UV guidance: Sunday’s UV 7 (high) and Monday’s UV 8 (very high) call for sun protection during peak hours.
- Hydration: Monday’s humidex 29 will feel warmer than the air temperature; plan breaks in the shade.
- Showers: Keep rain gear handy for Monday night and especially Tuesday with the higher chance of precipitation.
At a glance: forecast highlights
| Period | Conditions | Temp (°C) | Precip. chance |
|---|---|---|---|
| Today (Sun) | Sunny; light winds | High 22 | — |
| Tonight | Clear | Low 10 | — |
| Monday | Sunny; S wind late | High 26 (Humidex 29) | — |
| Mon night | Cloudy periods | Low 18 | 40% |
| Tuesday | Cloudy | High 21 | 60% |
| Tue night | Cloudy periods | Low 12 | 30% |
| Wednesday | Cloudy | High 19 | — |
| Thursday | Sunny | High 23 | — |
| Friday | Mix of sun and cloud | High 24 | — |
| Fri night | Cloudy periods | Low 16 | 60% |
| Saturday | Sun and cloud | High 24 | 30% |
Compared with the stated normals of 26 C for daytime highs and 15 C overnight, today’s cooler spell bookends a warmer, more humid Monday before a brief, unsettled stretch. The late-week picture suggests a return to near-seasonal temperatures under brighter skies.
This forecast is based on Environment Canada data for Newmarket and is current as of late Sunday morning. Conditions can change; residents should check for updates through the day.
