Ottawa residents planning patio time or a last long walk before fall sets in should keep one eye on the sky this weekend, because the forecast is calling for a mix of sun and rain over the next two days.
Saturday: warm start, stormy finish
Saturday begins cloudy but clears late in the morning, with Environment Canada calling for a high of 25°C across the city. It will feel warmer than that though: the humidex is expected to climb to 30, and the UV index sits at 6, or high, so sunscreen is worth packing if you're heading outside for the afternoon. Wind will pick up from the south at 20 km/h late in the morning.
The pleasant stretch doesn't last into the evening. Environment Canada says Ottawa will turn cloudy Saturday night with showers moving in, and there's a risk of a thunderstorm late in the evening continuing into the overnight hours. Wind will ease off from 20 km/h to light as the evening goes on, and the overnight low is set to drop to 18°C.
Sunday: showers clearing to a cooler night
Sunday carries some of Saturday night's wet weather into the morning, with a few showers expected before the skies clear in the afternoon. The high is forecast to match Saturday's at 25°C, with wind becoming southwest at 20 km/h late in the morning. Humidex values will actually edge higher than Saturday, reaching 32, though the UV index drops to 5, a moderate reading.
Once the sun sets Sunday, Ottawa should expect cloudy periods with a 40 percent chance of showers, and temperatures will fall much further than the previous night, down to a low of 8°C. That's a reminder that while the days still feel like summer, the nights are firmly shifting toward fall.
What it means for weekend plans in Ottawa
For anyone in Ottawa with outdoor plans this weekend, the takeaway is simple: get out and enjoy the warmth and sunshine during the day, but build in a backup plan for Saturday evening and Sunday morning. Patios, parks and any events without cover could see a soggy interruption right around Saturday night, and the risk of a thunderstorm means it's worth keeping an eye on the radar if you're out late. Sunday afternoon looks like the better bet for anything that needs dry, clear conditions, once the morning showers move through.
The swing between a 25°C, humid afternoon and an 8°C night by Sunday is also a good sign of where Ottawa sits in the calendar: still capable of summer-like warmth, but with cold fronts and cooler nights becoming the norm as September rolls on.
Earlier this month
Ottawa's shifting weather pattern has been a theme lately. ottown's earlier report looked at what CTV News expects for the broader fall forecast, while a scrapped AC/DC show in Toronto, covered in ottown's earlier report, was a reminder that storm damage this season has already disrupted plans well beyond just the weather itself.
Sources: Environment Canada
