Subj : Southern Ontario Weather To : All From : Northern Realms Date : Tue Sep 16 2025 15:35:00 FPCN11 CWTO 161930 Forecasts for Southern Ontario and the National Capital Region issued by Environment Canada at 3:30 p.m. EDT Tuesday 16 September 2025 for tonight Wednesday and Wednesday night. The next scheduled forecast will be issued at 5:00 a.m. EDT Wednesday. City of Toronto. Tonight..Clear. Low 14. Wednesday..Sunny. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 16. Windsor - Leamington - Essex County. Tonight..Clear. Fog patches developing overnight. Low 13. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 32. UV index 7 or high. Wednesday night..Clear. Low 13. Chatham-Kent - Rondeau Park. Tonight..Clear. Fog patches developing overnight. Low 12. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 32. UV index 7 or high. Wednesday night..Clear. Low 13. Sarnia - Petrolia - Western Lambton County. Tonight..A few clouds. Fog patches developing overnight. Low 11. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 12. Watford - Pinery Park - Eastern Lambton County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 12. Rodney - Shedden - Western Elgin County. Tonight..A few clouds. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 7 or high. Wednesday night..Clear. Low 11. St. Thomas - Aylmer - Eastern Elgin County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 7 or high. Wednesday night..Clear. Low 11. Strathroy - Komoka - Western Middlesex County. Tonight..Partly cloudy. Becoming clear late this evening. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 12. London - Parkhill - Eastern Middlesex County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 12. Simcoe - Delhi - Norfolk. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 10. Dunnville - Caledonia - Haldimand. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 32. UV index 7 or high. Wednesday night..Clear. Low 11. Woodstock - Tillsonburg - Oxford County. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 10. Brantford - County of Brant. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 10. Niagara Falls - Welland - Southern Niagara Region. Tonight..Clear. Fog patches developing overnight. Low 12. Wednesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 14. St. Catharines - Grimsby - Northern Niagara Region. Tonight..Clear. Fog patches developing overnight. Low 12. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 24. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 14. City of Hamilton. Tonight..Clear. Fog patches developing overnight. Low 13. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 25. Humidex 30. UV index 7 or high. Wednesday night..Clear. Low 13. Burlington - Oakville. Tonight..Clear. Low 13. Wednesday..A mix of sun and cloud. Becoming sunny in the morning. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 13. Halton Hills - Milton. Tonight..Clear. Low 11. Wednesday..Sunny. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 13. Mississauga - Brampton. Tonight..Clear. Low 13. Wednesday..Sunny. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 13. Caledon. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 13. Vaughan - Richmond Hill - Markham. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 11. Newmarket - Georgina - Northern York Region. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 11. Pickering - Oshawa - Southern Durham Region. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Uxbridge - Beaverton - Northern Durham Region. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 11. Goderich - Bluewater - Southern Huron County. Tonight..Clear. Low 10. Wednesday..Sunny. High 26. Humidex 29. UV index 6 or high. Wednesday night..A few clouds. Low 11. Wingham - Blyth - Northern Huron County. Tonight..Clear. Low 10. Wednesday..Sunny. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy overnight. Low 11. Stratford - Mitchell - Southern Perth County. Tonight..Clear. Low 9. Wednesday..Sunny. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 12. Listowel - Milverton - Northern Perth County. Tonight..Clear. Low 9. Wednesday..Sunny. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 12. Kitchener - Cambridge - Region of Waterloo. Tonight..Clear. Fog patches developing overnight. Low 7. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 10. Guelph - Erin - Southern Wellington County. Tonight..Clear. Fog patches developing overnight. Low 7. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 10. Mount Forest - Arthur - Northern Wellington County. Tonight..Clear. Fog patches developing overnight. Low 7. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 29. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy before morning. Low 10. Orangeville - Grand Valley - Southern Dufferin County. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Shelburne - Mansfield - Northern Dufferin County. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Innisfil - New Tecumseth - Angus. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Saugeen Shores - Kincardine - Southern Bruce County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy after midnight. Low 14. Bruce Peninsula - Sauble Beach - Tobermory. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Increasing cloudiness. Low 14. Hanover - Dundalk - Southern Grey County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy after midnight. Low 14. Owen Sound - Blue Mountains - Northern Grey County. Tonight..Clear. Fog patches developing overnight. Low 11. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy near midnight. Low 14. Barrie - Collingwood - Hillsdale. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 26. UV index 6 or high. Wednesday night..Clear. Low 12. Midland - Coldwater - Orr Lake. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 26. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy after midnight. Low 12. Orillia - Lagoon City - Washago. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 26. UV index 6 or high. Wednesday night..Clear. Low 12. Cobourg - Colborne - Western Northumberland County. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 23. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Belleville - Quinte West - Eastern Northumberland County. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 23. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Picton - Sandbanks Park. Tonight..Clear. Low 10. Wednesday..Mainly sunny. High 23. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Napanee - Consecon. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 23. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Kingston - Odessa - Frontenac Islands. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 23. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 11. Lindsay - Southern Kawartha Lakes. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Fenelon Falls - Balsam Lake Park - Northern Kawartha Lakes. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Peterborough City - Lakefield - Southern Peterborough County. Tonight..Clear. Fog patches developing overnight. Low 6. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 8. Apsley - Woodview - Northern Peterborough County. Tonight..Clear. Fog patches developing overnight. Low 6. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 8. Stirling - Tweed - Madoc. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 27. UV index 6 or high. Wednesday night..Clear. Low 11. Tamworth - Sydenham - South Frontenac. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 24. Humidex 27. UV index 6 or high. Wednesday night..Clear. Low 11. Kaladar - Bannockburn - Bon Echo Park. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 10. Bancroft - Hastings Highlands - Denbigh. Tonight..Clear. Fog patches developing overnight. Low 6. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 28. UV index 6 or high. Wednesday night..Clear. Low 8. Gananoque - Mallorytown. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. Wind south 20 km/h becoming light late in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Brockville - Prescott. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Westport - Charleston Lake. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Merrickville-Wolford - Kemptville. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Ottawa North - Kanata - Orl‚ans. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 14. Ottawa South - Richmond - Metcalfe. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 14. Gatineau. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 27. Humidex 30. UV index 6 or high. Wednesday night..A few clouds. Low 13. Prescott and Russell. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 14. Morrisburg - Long Sault. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Cornwall - Lancaster. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Winchester - Newington. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Maxville - Alexandria. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 30. UV index 6 or high. Wednesday night..Clear. Low 13. Plevna - Sharbot Lake - Western Lanark County. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 11. Smiths Falls - Perth - Eastern Lanark County. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Mainly sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 11. Port Carling - Port Severn. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy after midnight. Low 12. Bracebridge - Gravenhurst. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Becoming partly cloudy overnight. Low 12. Town of Parry Sound - Rosseau - Killbear Park. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Increasing cloudiness near midnight then 30 percent chance of showers before morning. Low 12. Huntsville - Baysville. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear in the evening and after midnight then partly cloudy with 30 percent chance of showers before morning. Low 12. Haliburton - Minden - Southern Haliburton County. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 27. UV index 6 or high. Wednesday night..Clear. Low 12. Oxtongue Lake - Fort Irwin - Northern Haliburton County. Tonight..Clear. Fog patches developing overnight. Low 10. Wednesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 27. UV index 6 or high. Wednesday night..Clear. Low 12. Barry's Bay - Killaloe. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 12. Renfrew - Arnprior - Calabogie. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 12. Petawawa - Pembroke - Cobden. Tonight..Clear. Fog patches developing overnight. Low 9. Wednesday..Sunny. Fog patches dissipating in the morning. High 26. Humidex 29. UV index 6 or high. Wednesday night..Clear. Low 12. Western Algonquin Park - Lake of Two Rivers. Tonight..Clear. Fog patches developing overnight. Low plus 5. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Partly cloudy before morning with 30 percent chance of showers. Low 9. Deep River - Whitney - Eastern Algonquin Park. Tonight..Clear. Fog patches developing overnight. Low plus 5. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear. Partly cloudy before morning with 30 percent chance of showers. Low 9. Bayfield Inlet - Dunchurch. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear in the evening and after midnight then partly cloudy with 30 percent chance of showers before morning. Low 14. South River - Burk's Falls. Tonight..Clear. Fog patches developing overnight. Low 8. Wednesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 28. UV index 6 or high. Wednesday night..Clear in the evening and after midnight then partly cloudy with 30 percent chance of showers before morning. Low 14. End $$$$^^ --- up 5 days, 18 hours, 10 minutes * Origin: Northern Realms (1:229/664) .