FPCN11 CWTO 212233 AAA UPDATED FORECASTS FOR SOUTHERN ONTARIO AND THE NATIONAL CAPITAL REGION ISSUED BY ENVIRONMENT CANADA AT 6:31 P.M. EDT SUNDAY 21 JUNE 2026 FOR TONIGHT MONDAY AND MONDAY NIGHT. THE NEXT SCHEDULED FORECAST WILL BE ISSUED AT 5:00 A.M. EDT MONDAY. WINDSOR - LEAMINGTON - ESSEX COUNTY. TONIGHT..CLOUDY. 30 PERCENT CHANCE OF SHOWERS THIS EVENING. PERIODS OF RAIN BEGINNING LATE THIS EVENING. LOCAL AMOUNT 10 TO 15 MM. WIND BECOMING NORTHEAST 20 KM/H GUSTING TO 40 BEFORE MORNING. LOW 14. MONDAY..RAIN ENDING IN THE MORNING THEN MAINLY CLOUDY WITH 40 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 15 MM. WIND NORTHEAST 20 KM/H GUSTING TO 40 BECOMING LIGHT IN THE AFTERNOON. HIGH 23. HUMIDEX 27. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY. FOG PATCHES DEVELOPING OVERNIGHT. LOW 9. CHATHAM-KENT - RONDEAU PARK. TONIGHT..MAINLY CLOUDY. PERIODS OF RAIN BEGINNING LATE THIS EVENING. LOCAL AMOUNT 10 TO 15 MM. LOW 14. MONDAY..RAIN ENDING IN THE MORNING THEN CLOUDY WITH 40 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 15 MM. WIND NORTHEAST 20 KM/H GUSTING TO 40. HIGH 22. HUMIDEX 26. UV INDEX 6 OR HIGH. MONDAY NIGHT..CLEAR. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTHEAST 20 KM/H GUSTING TO 40 BECOMING LIGHT LATE IN THE EVENING. LOW 9. SARNIA - PETROLIA - WESTERN LAMBTON COUNTY. TONIGHT..CLOUDY. PERIODS OF RAIN BEGINNING NEAR MIDNIGHT. LOCAL AMOUNT 5 TO 10 MM. LOW 14. MONDAY..PERIODS OF RAIN ENDING IN THE MORNING THEN A MIX OF SUN AND CLOUD WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 5 TO 10 MM. WIND BECOMING NORTH 20 KM/H IN THE MORNING. HIGH 23. HUMIDEX 26. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. OTHERWISE CLEAR. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTH 20 KM/H BECOMING LIGHT IN THE EVENING. LOW 10. WATFORD - PINERY PARK - EASTERN LAMBTON COUNTY. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT THEN PERIODS OF RAIN. LOCAL AMOUNT 5 TO 10 MM. LOW 14. MONDAY..PERIODS OF RAIN ENDING IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 5 TO 10 MM. HIGH 23. HUMIDEX 26. UV INDEX 6 OR HIGH. MONDAY NIGHT..MAINLY CLOUDY. 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING BEFORE MORNING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 10. RODNEY - SHEDDEN - WESTERN ELGIN COUNTY. TONIGHT..CLOUDY. PERIODS OF RAIN BEGINNING AFTER MIDNIGHT. LOCAL AMOUNT 5 TO 10 MM. LOW 14. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 20 MM. WIND NORTHEAST 20 KM/H. HIGH 22. HUMIDEX 26. UV INDEX 7 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING IN THE EVENING. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTH 20 KM/H BECOMING LIGHT EARLY IN THE EVENING. LOW 9. ST. THOMAS - AYLMER - EASTERN ELGIN COUNTY. TONIGHT..MAINLY CLOUDY. PERIODS OF RAIN BEGINNING AFTER MIDNIGHT. LOCAL AMOUNT 5 TO 10 MM. LOW 14. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 20 MM. WIND BECOMING NORTHEAST 20 KM/H IN THE MORNING. HIGH 22. HUMIDEX 26. UV INDEX 7 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING IN THE EVENING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 9. STRATHROY - KOMOKA - WESTERN MIDDLESEX COUNTY. TONIGHT..MAINLY CLOUDY. PERIODS OF RAIN BEGINNING AFTER MIDNIGHT. LOCAL AMOUNT 5 TO 10 MM. LOW 14. MONDAY..PERIODS OF RAIN ENDING IN THE MORNING THEN MAINLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 5 TO 10 MM. WIND BECOMING NORTHEAST 20 KM/H LATE IN THE MORNING. HIGH 24. HUMIDEX 26. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. OTHERWISE CLEAR. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTHWEST 20 KM/H BECOMING LIGHT IN THE EVENING. LOW 10. LONDON - PARKHILL - EASTERN MIDDLESEX COUNTY. TONIGHT..BECOMING CLOUDY LATE THIS EVENING. PERIODS OF RAIN BEGINNING AFTER MIDNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING IN THE MORNING THEN MAINLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. HIGH 24. HUMIDEX 26. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING IN THE EVENING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 10. SIMCOE - DELHI - NORFOLK. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT. PERIODS OF RAIN BEGINNING OVERNIGHT. LOW 13. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 15 TO 25 MM. HIGH 20. UV INDEX 6 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY. 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING BEFORE MORNING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 8. DUNNVILLE - CALEDONIA - HALDIMAND. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT WITH 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING EARLY IN THE AFTERNOON THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 15 TO 25 MM. WIND NORTHEAST 20 KM/H BECOMING LIGHT EARLY IN THE AFTERNOON. HIGH 20. UV INDEX 6 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY. FOG PATCHES DEVELOPING OVERNIGHT. LOW 12. WOODSTOCK - TILLSONBURG - OXFORD COUNTY. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT. 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN MAINLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 15 MM. HIGH 22. HUMIDEX 25. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING IN THE EVENING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 8. BRANTFORD - COUNTY OF BRANT. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT WITH 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 15 MM. WIND NORTHEAST 20 KM/H BECOMING LIGHT NEAR NOON. HIGH 20. UV INDEX 7 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY. 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING BEFORE MORNING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 8. NIAGARA FALLS - WELLAND - SOUTHERN NIAGARA REGION. TONIGHT..INCREASING CLOUDINESS. 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING EARLY IN THE AFTERNOON THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 15 TO 25 MM. WIND BECOMING NORTHEAST 20 KM/H IN THE MORNING. HIGH 20. HUMIDEX 25. UV INDEX 3 OR MODERATE. MONDAY NIGHT..CLOUDY. BECOMING PARTLY CLOUDY BEFORE MORNING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 13. ST. CATHARINES - GRIMSBY - NORTHERN NIAGARA REGION. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY AFTER MIDNIGHT WITH 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 14. MONDAY..PERIODS OF RAIN ENDING EARLY IN THE AFTERNOON THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 15 TO 25 MM. HIGH 19. UV INDEX 5 OR MODERATE. MONDAY NIGHT..CLOUDY. BECOMING PARTLY CLOUDY BEFORE MORNING. FOG PATCHES DEVELOPING OVERNIGHT. LOW 13. CITY OF HAMILTON. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY AFTER MIDNIGHT WITH 30 PERCENT CHANCE OF SHOWERS OVERNIGHT. LOW 13. MONDAY..PERIODS OF RAIN ENDING LATE IN THE MORNING THEN CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. LOCAL AMOUNT 10 TO 15 MM. WIND NORTHEAST 20 KM/H BECOMING LIGHT EARLY IN THE AFTERNOON. HIGH 19. UV INDEX 6 OR HIGH. MONDAY NIGHT..CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. CLEARING NEAR MIDNIGHT. FOG PATCHES DEVELOPING OVERNIGHT. LOW 10. GODERICH - BLUEWATER - SOUTHERN HURON COUNTY. TONIGHT..INCREASING CLOUDINESS EARLY THIS EVENING. 30 PERCENT CHANCE OF SHOWERS BEFORE MORNING. LOW 15. MONDAY..A MIX OF SUN AND CLOUD WITH 30 PERCENT CHANCE OF SHOWERS. WIND BECOMING NORTHWEST 20 KM/H GUSTING TO 40 NEAR NOON. HIGH 24. UV INDEX 8 OR VERY HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. OTHERWISE CLEAR. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTHWEST 20 KM/H GUSTING TO 40. LOW 6. STRATFORD - MITCHELL - SOUTHERN PERTH COUNTY. TONIGHT..PARTLY CLOUDY. BECOMING CLOUDY NEAR MIDNIGHT. 30 PERCENT CHANCE OF SHOWERS BEFORE MORNING. LOW 14. MONDAY..MAINLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS. HIGH 24. HUMIDEX 26. UV INDEX 7 OR HIGH. MONDAY NIGHT..PARTLY CLOUDY WITH 30 PERCENT CHANCE OF SHOWERS EARLY IN THE EVENING. OTHERWISE CLEAR. FOG PATCHES DEVELOPING OVERNIGHT. WIND NORTH 20 KM/H BECOMING LIGHT AFTER MIDNIGHT. LOW 7. REMAINDER UNCHANGED. END