Thunder Bay weather live forecast

Today's maximum temperature in Thunder Bay is expected to be 13°C. Select a day from the live weather forecast for Thunder Bay, Ontario, Canada for more weather parameters.

  • Monday
    18th May
    Isolated thunderstorms (5-10 mm of rainfall expected)
  • Tuesday
    19th May
    Isolated thunderstorms (10-20 mm of rainfall expected)
  • Wednesday
    20th May
    Broken clouds
  • Thursday
    21st May
    Scattered clouds
  • Friday
    22nd May
    Sunshine and showers (0-2 mm of rainfall expected)

5-day weather forecast updated at 04:00 on Monday 18th May 2026 GMT

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The 5-day weather forecast for Ontario (Thunder Bay) is provided by the Swiss meteorological agency, meteoblue. Find out more about our data sources.

Thunder Bay weather forecast by day

Below are the detailed weather forecasts for Thunder Bay for the next 5 days.

Thunder Bay weather for Monday 18th May 2026

Expect isolated thunderstorms in Thunder Bay, Ontario with a maximum temperature of 13°C, maximum UV of 3 (Moderate) and 1 hour of bright sunshine. There are 5-10 mm of rainfall expected with 49% chance of some rain and a gentle breeze of 16 kph from the north-east.

  • 13°C maximum temperature13
    °C maximum temperature
  • 6°C minimum temperature6
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 1 hour of bright sunshine1
    hour of sunshine
  • UV (maximum) index 3 (Moderate)3
    UV index (Moderate)
  • 49% chance of some rain49
    % chance of some rain
  • 5-10 mm of rainfall expected<10
    mm of rainfall expected
  • No heat & humidity0
    no heat & humidity
  • Gentle breeze of 16 kph from the North-East16
    kph wind from NE

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Thunder Bay weather for Tuesday 19th May 2026

Expect isolated thunderstorms in Thunder Bay, Ontario with a maximum temperature of 7°C, maximum UV of 3 (Moderate) and no hours of bright sunshine. There are 10-20 mm of rainfall expected with 41% chance of some rain and a moderate breeze of 20 kph from the north-west.

  • 7°C maximum temperature7
    °C maximum temperature
  • 2°C minimum temperature2
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • No hours of bright sunshine0
    hours of sunshine
  • UV (maximum) index 3 (Moderate)3
    UV index (Moderate)
  • 41% chance of some rain41
    % chance of some rain
  • 10-20 mm of rainfall expected<20
    mm of rainfall expected
  • 4°C wind chill4
    °C wind chill
  • Moderate breeze of 20 kph from the North-West20
    kph wind from NW

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Thunder Bay weather for Wednesday 20th May 2026

Expect broken clouds in Thunder Bay, Ontario with a maximum temperature of 12°C, maximum UV of 3 (Moderate) and 4 hours of bright sunshine. There are 0 mm of rainfall expected and a gentle breeze of 16 kph from the north-west.

  • 12°C maximum temperature12
    °C maximum temperature
  • 0°C minimum temperature0
    °C minimum temperature
  • Broken clouds
    broken clouds
  • 4 hours of bright sunshine4
    hours of sunshine
  • UV (maximum) index 3 (Moderate)3
    UV index (Moderate)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • No heat & humidity0
    no heat & humidity
  • Gentle breeze of 16 kph from the North-West16
    kph wind from NW

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Thunder Bay weather for Thursday 21st May 2026

Expect scattered clouds in Thunder Bay, Ontario with a maximum temperature of 14°C, maximum UV of 6 (High) and 11 hours of bright sunshine. There are 0 mm of rainfall expected and a gentle breeze of 18 kph from the south.

  • 14°C maximum temperature14
    °C maximum temperature
  • 1°C minimum temperature1
    °C minimum temperature
  • Scattered clouds
    scattered clouds
  • 11 hours of bright sunshine11
    hours of sunshine
  • UV (maximum) index 6 (High)6
    UV index (High)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • 14°C wind chill14
    °C wind chill
  • Gentle breeze of 18 kph from the South18
    kph wind from S

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Thunder Bay weather for Friday 22nd May 2026

Expect sunshine and showers in Thunder Bay, Ontario with a maximum temperature of 14°C, maximum UV of 6 (High) and 8 hours of bright sunshine. There are 0-2 mm of rainfall expected with 43% chance of some rain and a gentle breeze of 15 kph from the south-east.

  • 14°C maximum temperature14
    °C maximum temperature
  • 3°C minimum temperature3
    °C minimum temperature
  • Sunshine and showers
    sunshine and showers
  • 8 hours of bright sunshine8
    hours of sunshine
  • UV (maximum) index 6 (High)6
    UV index (High)
  • 43% chance of some rain43
    % chance of some rain
  • 0-2 mm of rainfall expected<2
    mm of rainfall expected
  • 14°C wind chill14
    °C wind chill
  • Gentle breeze of 15 kph from the South-East15
    kph wind from SE

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