Subj : Southern Ontario Weather To : All From : Northern Realms Date : Tue Jul 22 2025 15:35:00 FPCN11 CWTO 221930 Forecasts for Southern Ontario and the National Capital Region issued by Environment Canada at 3:30 p.m. EDT Tuesday 22 July 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..Clearing. Low 17. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clearing in the evening. Low 19. Windsor - Leamington - Essex County. Tonight..Clear. Low 16. Wednesday..Sunny. High 30. Humidex 34. UV index 10 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 20. Chatham-Kent - Rondeau Park. Tonight..Clear. Low 15. Wednesday..Sunny. High 30. Humidex 34. UV index 10 or very high. Wednesday night..Clear. Low 20. Sarnia - Petrolia - Western Lambton County. Tonight..Partly cloudy. Becoming clear this evening. Low 13. Wednesday..Sunny. Wind becoming south 20 km/h late in the morning. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clear. Wind becoming south 20 km/h in the evening. Low 19. Watford - Pinery Park - Eastern Lambton County. Tonight..Partly cloudy. Becoming clear this evening. Low 13. Wednesday..Sunny. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 19. Rodney - Shedden - Western Elgin County. Tonight..Clear. Low 14. Wednesday..Sunny. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 19. St. Thomas - Aylmer - Eastern Elgin County. Tonight..Clear. Low 14. Wednesday..Sunny. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 19. Strathroy - Komoka - Western Middlesex County. Tonight..Partly cloudy. Becoming clear this evening. Low 13. Wednesday..Sunny. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Low 18. London - Parkhill - Eastern Middlesex County. Tonight..Partly cloudy. Becoming clear this evening. Low 13. Wednesday..Sunny. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Low 18. Simcoe - Delhi - Norfolk. Tonight..Partly cloudy. Becoming clear this evening. Low 12. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Low 17. Dunnville - Caledonia - Haldimand. Tonight..Partly cloudy. Becoming clear this evening. Low 14. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 18. Woodstock - Tillsonburg - Oxford County. Tonight..Clear. Low 12. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 34. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 17. Brantford - County of Brant. Tonight..Clear. Low 12. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 34. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 17. Niagara Falls - Welland - Southern Niagara Region. Tonight..Partly cloudy. Becoming clear this evening. Low 16. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 36. UV index 9 or very high. Wednesday night..Clear. Low 19. St. Catharines - Grimsby - Northern Niagara Region. Tonight..Partly cloudy. Becoming clear this evening. Low 16. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Wind becoming south 20 km/h before morning. Low 19. City of Hamilton. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 18. Burlington - Oakville. Tonight..Clear. Low 16. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 18. Halton Hills - Milton. Tonight..Clear. Low 15. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 18. Mississauga - Brampton. Tonight..Clearing. Low 16. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clearing in the evening. Low 18. Caledon. Tonight..Clearing. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming south 20 km/h in the afternoon. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clearing in the evening. Wind south 20 km/h becoming light in the evening. Wind becoming southwest 20 gusting to 40 after midnight. Low 17. Vaughan - Richmond Hill - Markham. Tonight..Clearing. Low 15. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clearing in the evening. Low 18. Newmarket - Georgina - Northern York Region. Tonight..Clearing. Low 14. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming south 20 km/h late in the afternoon. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clearing in the evening. Wind south 20 km/h becoming light in the evening. Low 18. Pickering - Oshawa - Southern Durham Region. Tonight..Clearing. Low 14. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 28. Humidex 33. UV index 9 or very high. Wednesday night..Clearing in the evening. Low 17. Uxbridge - Beaverton - Northern Durham Region. Tonight..Clearing. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 28. Humidex 33. UV index 9 or very high. Wednesday night..Clearing in the evening. Wind becoming southwest 20 km/h before morning. Low 17. Goderich - Bluewater - Southern Huron County. Tonight..Clear. Low 14. Wednesday..Sunny. Wind becoming south 30 km/h in the afternoon. High 30. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Becoming partly cloudy after midnight. Wind south 30 km/h. Low 19. Wingham - Blyth - Northern Huron County. Tonight..Clear. Low 14. Wednesday..Sunny. Wind becoming south 20 km/h in the afternoon. High 30. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Becoming partly cloudy after midnight. Wind south 20 km/h. Low 19. Stratford - Mitchell - Southern Perth County. Tonight..Clear. Low 12. Wednesday..Sunny. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Becoming partly cloudy after midnight. Wind becoming southwest 20 km/h before morning. Low 18. Listowel - Milverton - Northern Perth County. Tonight..Clear. Low 12. Wednesday..Sunny. Wind becoming south 20 km/h in the afternoon. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Becoming partly cloudy after midnight. Wind south 20 km/h becoming light in the evening. Low 18. Kitchener - Cambridge - Region of Waterloo. Tonight..Clear. Low 12. Wednesday..Sunny. Wind becoming south 20 km/h late in the afternoon. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h. Low 17. Guelph - Erin - Southern Wellington County. Tonight..Clear. Low 12. Wednesday..Sunny. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Low 17. Mount Forest - Arthur - Northern Wellington County. Tonight..Clear. Low 12. Wednesday..Sunny. Wind becoming south 20 km/h in the afternoon. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h. Low 17. Orangeville - Grand Valley - Southern Dufferin County. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming south 20 km/h in the afternoon. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind southwest 20 km/h becoming light in the evening. Wind becoming southwest 20 gusting to 40 after midnight. Low 18. Shelburne - Mansfield - Northern Dufferin County. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming south 20 km/h in the afternoon. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Wind becoming southwest 20 gusting to 40 before morning. Low 18. Innisfil - New Tecumseth - Angus. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming south 20 km/h in the afternoon. High 30. Humidex 35. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h. Low 17. Saugeen Shores - Kincardine - Southern Bruce County. Tonight..Clear. Low 16. Wednesday..Sunny. Wind southwest 20 km/h becoming light late in the morning. Wind becoming south 20 gusting to 40 in the afternoon. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h gusting to 40. Low 19. Bruce Peninsula - Sauble Beach - Tobermory. Tonight..Clear. Wind becoming south 20 km/h before morning. Low 16. Wednesday..Sunny. Wind south 30 km/h gusting to 50. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear early in the evening then partly cloudy with 40 percent chance of showers overnight. Risk of a thunderstorm overnight. Wind south 30 km/h gusting to 50. Low 19. Hanover - Dundalk - Southern Grey County. Tonight..Clear. Low 14. Wednesday..Sunny. Wind south 20 km/h. High 30. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Wind becoming southwest 20 gusting to 40 after midnight. Low 19. Owen Sound - Blue Mountains - Northern Grey County. Tonight..Clear. Low 14. Wednesday..Sunny. Wind southwest 20 km/h becoming light late in the morning. High 30. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h gusting to 40 in the evening. Low 19. Barrie - Collingwood - Hillsdale. Tonight..Clear. Low 13. Wednesday..Sunny. Wind becoming south 20 km/h in the afternoon. High 30. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Low 17. Midland - Coldwater - Orr Lake. Tonight..Clear. Low 15. Wednesday..Sunny. Wind becoming south 20 km/h in the afternoon. High 28. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h. Low 18. Orillia - Lagoon City - Washago. Tonight..Clear. Wind becoming south 20 km/h this evening. Low 15. Wednesday..Sunny. Wind becoming south 20 km/h late in the afternoon. High 28. Humidex 35. UV index 9 or very high. Wednesday night..Clear. Wind south 30 km/h. Low 22. Cobourg - Colborne - Western Northumberland County. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 18. Belleville - Quinte West - Eastern Northumberland County. Tonight..Clear. Low 14. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 18. Picton - Sandbanks Park. Tonight..Clear. Low 15. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 19. Napanee - Consecon. Tonight..Clear. Low 13. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 19. Kingston - Odessa - Frontenac Islands. Tonight..Clear. Low 14. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 19. Lindsay - Southern Kawartha Lakes. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 30. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 17. Fenelon Falls - Balsam Lake Park - Northern Kawartha Lakes. Tonight..Clear. Low 10. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 30. UV index 9 or very high. Wednesday night..Clear. Low 17. Peterborough City - Lakefield - Southern Peterborough County. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 16. Apsley - Woodview - Northern Peterborough County. Tonight..Clear. Low 9. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 16. Stirling - Tweed - Madoc. Tonight..Clear. Low 12. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 18. Tamworth - Sydenham - South Frontenac. Tonight..Clear. Low 12. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 18. Kaladar - Bannockburn - Bon Echo Park. Tonight..Clear. Low 8. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 15. Bancroft - Hastings Highlands - Denbigh. Tonight..Clear. Low 8. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. Wind southwest 20 km/h. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Low 15. Gananoque - Mallorytown. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 29. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 19. Brockville - Prescott. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 29. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 18. Westport - Charleston Lake. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 29. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Low 18. Merrickville-Wolford - Kemptville. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 29. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 18. Ottawa North - Kanata - Orl‚ans. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind becoming south 20 km/h before morning. Low 17. Ottawa South - Richmond - Metcalfe. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Clear. Wind becoming south 20 km/h before morning. Low 17. Gatineau. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Low 17. Prescott and Russell. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 15. Morrisburg - Long Sault. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 17. Cornwall - Lancaster. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. Wind becoming southwest 20 km/h in the afternoon. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind southwest 20 km/h becoming light in the evening. Wind becoming southwest 30 before morning. Low 17. Winchester - Newington. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 17. Maxville - Alexandria. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud late in the morning. High 27. Humidex 31. UV index 9 or very high. Wednesday night..Partly cloudy. Becoming clear in the evening. Wind becoming southwest 20 km/h before morning. Low 17. Plevna - Sharbot Lake - Western Lanark County. Tonight..Clear. Low 10. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Low 16. Smiths Falls - Perth - Eastern Lanark County. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Wind becoming southwest 20 km/h before morning. Low 17. Port Carling - Port Severn. Tonight..Clear. Low 16. Wednesday..Sunny. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Wind becoming south 20 km/h in the evening. Low 18. Bracebridge - Gravenhurst. Tonight..Clear. Low 14. Wednesday..Sunny. Wind becoming south 20 km/h late in the afternoon. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Low 17. Town of Parry Sound - Rosseau - Killbear Park. Tonight..Clear. Low 16. Wednesday..Mainly sunny. Wind becoming south 30 km/h late in the afternoon. High 29. Humidex 33. UV index 9 or very high. Wednesday night..Clear in the evening then partly cloudy with 40 percent chance of showers overnight. Risk of a thunderstorm overnight. Wind south 30 km/h. Low 19. Huntsville - Baysville. Tonight..Clear. Low 13. Wednesday..Mainly sunny. Wind becoming south 20 km/h in the afternoon. High 27. Humidex 32. UV index 9 or very high. Wednesday night..Clear in the evening then partly cloudy with 40 percent chance of showers overnight. Risk of a thunderstorm overnight. Low 17. Haliburton - Minden - Southern Haliburton County. Tonight..Clear. Low 10. Wednesday..Sunny. Wind becoming southwest 20 km/h in the afternoon. High 27. Humidex 31. UV index 9 or very high. Wednesday night..A few clouds. Wind south 20 km/h becoming light in the evening. Low 16. Oxtongue Lake - Fort Irwin - Northern Haliburton County. Tonight..Clear. Low 9. Wednesday..Sunny. Wind southwest 20 km/h. High 27. Humidex 31. UV index 9 or very high. Wednesday night..A few clouds. Low 16. Barry's Bay - Killaloe. Tonight..Clear. Low 9. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. Wind becoming southwest 20 km/h in the morning. High 28. Humidex 31. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h. Low 16. Renfrew - Arnprior - Calabogie. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. Wind southwest 20 km/h. High 29. Humidex 32. UV index 9 or very high. Wednesday night..Clear. Wind south 20 km/h becoming light in the evening. Low 18. Petawawa - Pembroke - Cobden. Tonight..Clear. Low 11. Wednesday..Sunny. Becoming a mix of sun and cloud in the morning. High 29. Humidex 34. UV index 9 or very high. Wednesday night..Clear. Low 18. Western Algonquin Park - Lake of Two Rivers. Tonight..Clear. Low 8. Wednesday..Sunny. Wind becoming southwest 20 km/h in the morning. High 27. Humidex 31. UV index 9 or very high. Wednesday night..A few clouds. Wind becoming southwest 20 km/h near midnight. Low 16. Deep River - Whitney - Eastern Algonquin Park. Tonight..Clear. Low 8. Wednesday..Sunny. Wind becoming southwest 20 km/h in the morning. High 27. Humidex 31. UV index 9 or very high. Wednesday night..A few clouds. Wind southwest 20 km/h. Low 16. Bayfield Inlet - Dunchurch. Tonight..Clear. Low 13. Wednesday..Mainly sunny. Wind becoming southwest 20 km/h late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Clear in the evening then partly cloudy with 40 percent chance of showers overnight. Risk of a thunderstorm overnight. Wind south 20 km/h becoming light after midnight. Low 19. South River - Burk's Falls. Tonight..Clear. Low 12. Wednesday..Mainly sunny. Wind becoming southwest 20 km/h late in the morning. High 27. Humidex 30. UV index 9 or very high. Wednesday night..Clear in the evening then partly cloudy with 40 percent chance of showers overnight. Risk of a thunderstorm overnight. Wind south 20 km/h becoming light after midnight. Low 18. End $$$$^^ --- up 4 days, 10 hours, 37 minutes * Origin: Northern Realms (1:229/664) .