Subj : Southern Ontario Weather To : All From : Northern Realms Date : Mon Sep 29 2025 11:05:00 FPCN11 CWTO 291500 Forecasts for Southern Ontario and the National Capital Region issued by Environment Canada at 11:00 a.m. EDT Monday 29 September 2025 for today and Tuesday. The next scheduled forecast will be issued at 3:30 p.m. EDT. City of Toronto. Today..Sunny. High 24. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Windsor - Leamington - Essex County. Today..Sunny. High 26. Humidex 29. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 11. Tuesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 27. Chatham-Kent - Rondeau Park. Today..Sunny. High 26. Humidex 29. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 11. Tuesday..Sunny. Fog patches dissipating in the morning. High 25. Humidex 27. Sarnia - Petrolia - Western Lambton County. Today..Sunny. Fog patches dissipating early this afternoon. High 25. Humidex 28. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 26. Watford - Pinery Park - Eastern Lambton County. Today..Sunny. Fog patches dissipating early this afternoon. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 26. Rodney - Shedden - Western Elgin County. Today..Sunny. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 26. St. Thomas - Aylmer - Eastern Elgin County. Today..Sunny. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 26. Strathroy - Komoka - Western Middlesex County. Today..Sunny. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. High 24. Humidex 26. London - Parkhill - Eastern Middlesex County. Today..Sunny. High 25. Humidex 28. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Simcoe - Delhi - Norfolk. Today..Sunny. High 25. Humidex 28. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Dunnville - Caledonia - Haldimand. Today..Sunny. High 24. Humidex 26. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 12. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Woodstock - Tillsonburg - Oxford County. Today..Sunny. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Brantford - County of Brant. Today..Sunny. High 25. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 10. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Niagara Falls - Welland - Southern Niagara Region. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 12. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. St. Catharines - Grimsby - Northern Niagara Region. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 12. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. City of Hamilton. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 12. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Burlington - Oakville. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Halton Hills - Milton. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Mississauga - Brampton. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Caledon. Today..Sunny. High 24. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Vaughan - Richmond Hill - Markham. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Newmarket - Georgina - Northern York Region. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Pickering - Oshawa - Southern Durham Region. Today..Sunny. High 24. Humidex 27. UV index 6 or high. Tonight..Clear. Low 11. Tuesday..Sunny. Wind becoming east 20 km/h near noon. High 22. Uxbridge - Beaverton - Northern Durham Region. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Goderich - Bluewater - Southern Huron County. Today..Sunny. High 24. Humidex 27. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Wingham - Blyth - Northern Huron County. Today..Sunny. High 24. Humidex 26. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Stratford - Mitchell - Southern Perth County. Today..Sunny. High 24. Humidex 26. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 23. Humidex 25. Listowel - Milverton - Northern Perth County. Today..Sunny. High 24. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Kitchener - Cambridge - Region of Waterloo. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Guelph - Erin - Southern Wellington County. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Mount Forest - Arthur - Northern Wellington County. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Orangeville - Grand Valley - Southern Dufferin County. Today..Sunny. High 24. Humidex 25. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Shelburne - Mansfield - Northern Dufferin County. Today..Sunny. High 24. UV index 6 or high. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Innisfil - New Tecumseth - Angus. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Saugeen Shores - Kincardine - Southern Bruce County. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Bruce Peninsula - Sauble Beach - Tobermory. Today..Sunny. High 21. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 9. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h gusting to 40 near noon. High 20. Hanover - Dundalk - Southern Grey County. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Owen Sound - Blue Mountains - Northern Grey County. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. Wind becoming northeast 20 km/h near noon. High 22. Barrie - Collingwood - Hillsdale. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Midland - Coldwater - Orr Lake. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Orillia - Lagoon City - Washago. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Fog patches developing after midnight. Low 8. Tuesday..Sunny. Fog patches dissipating in the morning. High 22. Cobourg - Colborne - Western Northumberland County. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Belleville - Quinte West - Eastern Northumberland County. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Picton - Sandbanks Park. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Napanee - Consecon. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Kingston - Odessa - Frontenac Islands. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Lindsay - Southern Kawartha Lakes. Today..Sunny. High 24. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 21. Fenelon Falls - Balsam Lake Park - Northern Kawartha Lakes. Today..Sunny. High 24. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 21. Peterborough City - Lakefield - Southern Peterborough County. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 21. Apsley - Woodview - Northern Peterborough County. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 19. Stirling - Tweed - Madoc. Today..Sunny. High 25. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 20. Tamworth - Sydenham - South Frontenac. Today..Sunny. High 25. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 20. Kaladar - Bannockburn - Bon Echo Park. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 19. Bancroft - Hastings Highlands - Denbigh. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Gananoque - Mallorytown. Today..Sunny. High 23. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. Wind becoming northeast 20 km/h near noon. High 21. Brockville - Prescott. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Westport - Charleston Lake. Today..Sunny. High 25. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 20. Merrickville-Wolford - Kemptville. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Ottawa North - Kanata - Orleans. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Ottawa South - Richmond - Metcalfe. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Gatineau. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Prescott and Russell. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Morrisburg - Long Sault. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Cornwall - Lancaster. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Winchester - Newington. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Maxville - Alexandria. Today..Sunny. High 26. Humidex 27. UV index 5 or moderate. Tonight..Clear. Low 10. Tuesday..Sunny. High 19. Plevna - Sharbot Lake - Western Lanark County. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 19. Smiths Falls - Perth - Eastern Lanark County. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 19. Port Carling - Port Severn. Today..Sunny. Fog patches dissipating early this afternoon. High 21. UV index 5 or moderate. Tonight..Clear. Low 8. Tuesday..Sunny. High 19. Bracebridge - Gravenhurst. Today..Sunny. High 24. Humidex 25. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 21. Town of Parry Sound - Rosseau - Killbear Park. Today..Sunny. Fog patches dissipating early this afternoon. High 21. UV index 5 or moderate. Tonight..Clear. Low 8. Tuesday..Sunny. High 19. Huntsville - Baysville. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Haliburton - Minden - Southern Haliburton County. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Oxtongue Lake - Fort Irwin - Northern Haliburton County. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Barry's Bay - Killaloe. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Renfrew - Arnprior - Calabogie. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 18. Petawawa - Pembroke - Cobden. Today..Sunny. High 25. Humidex 26. UV index 5 or moderate. Tonight..Clear. Low 7. Tuesday..Sunny. High 18. Western Algonquin Park - Lake of Two Rivers. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Deep River - Whitney - Eastern Algonquin Park. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. Bayfield Inlet - Dunchurch. Today..Sunny. High 21. UV index 5 or moderate. Tonight..Clear. Low 8. Tuesday..Sunny. High 19. South River - Burk's Falls. Today..Sunny. High 23. UV index 5 or moderate. Tonight..Clear. Low 6. Tuesday..Sunny. High 17. End $$$$^^ --- up 1 day, 2 hours, 48 minutes * Origin: Northern Realms (618:400/23) .