AI-generatedSarnia at a glance
- Best time
- May – Sep
- Warmest month
- Jul · 28°
- Sunshine a year
- 2,070 h
- Rain a year
- 836 mm
- Climate
- Continental
- Time zone
- UTC−5 / UTC−4
- Elevation
- 185 m
Climate in Sarnia
Sarnia has warm to hot summers and cold winters with occasional snow. July is the warmest month with average highs of 28 °C, while January is the coolest at 0 °C. With around 2,070 hours of sunshine a year, Sarnia is moderately sunny; July is the sunniest month with 8.9 hours a day.
Holiday weather through the year
Best time to visit Sarnia
The best time to visit Sarnia is from May to September. For sightseeing, day trips and hiking, conditions are most comfortable from May to October. The wettest month is June with 86 mm of precipitation.
Sarnia through the seasons
How the weather changes over the seasons, with averages for each.
Sarnia in spring
Mar – May
Fair
- 6–20 °C by day
- 6.3 h of sun a day
- 33 rainy days in all
Sarnia in summer
Jun – Aug
Excellent
- 25–28 °C by day
- 8.3 h of sun a day
- 32 rainy days in all
Sarnia in autumn
Sep – Nov
Fair
- 9–23 °C by day
- 4.9 h of sun a day
- 29 rainy days in all
Sarnia in winter
Dec – Feb
Poor
- 0–3 °C by day
- 3.2 h of sun a day
- 28 rainy days in all
Which month for what?
Beach & swimming
No sea nearby
Sea from 21 °C, warm and mostly dry
Sightseeing & hiking
May – Oct
15–28 °C and not too much rain
Snow
Dec – Mar
Snow on 2 or more days
Find your perfect month
Tell us what you like and we rate every month in Sarnia for you.
Your best months: June, September
Based on the climate averages; tap a month to see its details.
Weather in October
Weather in October
Holiday weather in October
Good
Best time to visit: May – September
Good forSightseeing & walks
A typical day in October
- Morning, 08:00: about 8°
- Midday, 13:00: about 15°
- Afternoon, 16:00: about 16°
- Evening, 20:00: about 13°
- Night, 23:00: about 10°
07:4218:49
Cool evenings: pack a jumper or a jacket.
Estimated from the average high and low: coolest around sunrise, warmest in mid-afternoon.
Light for photos in October
- Golden hour
- Morning 07:24–08:20 · evening 18:10–19:06
- Blue hour
- Morning 07:13–07:24 · evening 19:06–19:17
Golden hour: the sun between 4° below and 6° above the horizon; blue hour: 6° to 4° below it. Times for the 15th of the month; mountains and clouds shift the light.
October in Sarnia compared with home
Loading the climate at home …
Early or late October?
In October, daytime highs fall from about 20° at the start of the month to 12° at the end. The days get 1.4 h shorter.
| October | 1 Oct | 31 Oct |
|---|---|---|
| Daytime high | 20° | 12° |
| Night-time low | 10° | 4° |
| Daylight | 11.8 h | 10.4 h |
What is the weather like in Sarnia in October?
In October, Sarnia is mild: daytime highs average 16 °C, and nights cool down to about 7 °C. Expect around 4.7 hours of sunshine a day. Rain is frequent, with about 11 rainy days and 75 mm in total. All in all, October is a good month for a holiday in Sarnia.
More details for October
- Daylight
- 11 h 7 min07:42 – 18:49
- UV index
- 3 · moderateclear sky, noon (estimate)All months
- Muggy days
- 1 daydew point 18 °C or moreAll months
- Wind
- 21 km/haverage daily peakAll months
- Cloud cover
- 60 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snowAll months
- Time zone
- UTC−4offset from UTC
How the score comes together
- Temperatureweight 50 %82 %
- Sunshineweight 20 %28 %
- Few rainy daysweight 30 %48 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in October
- Sunscreen
- A jumper for the evenings
- Rain jacket or umbrella
Compare two months in Sarnia
Pick two months to see how the weather differs. A tick marks the clearly better value; for temperatures it depends on your plans.
June has the better holiday weather in Sarnia: score 83 against 61. In June, days are 9 °C warmer than in October. The sun shines 4 hours longer a day in June.
| Month | October | June |
|---|---|---|
| Holiday weather score | 61 | 83better |
| Daytime high | 16° | 25° |
| Night-time low | 7° | 15° |
| Sunshine | 4.7 h | 8.5 hbetter |
| Rainy days | 11 | 11 |
| Rainfall | 75 mmbetter | 86 mm |
| Muggy days | 1better | 6 |
Based on the climate averages 1996–2025.
Sarnia month by month
The typical weather for every month at a glance.
18January0° · 3.0 h
In January, Sarnia is bitterly cold: daytime highs average 0 °C, and nights often drop below freezing (−8 °C). The sun is scarce, with only about 3.0 hours a day. Precipitation falls on about 10 days, totalling 56 mm; on about 6 of them it snows. All in all, January is not an ideal month for a holiday in Sarnia.
Sarnia in January24February1° · 4.2 h
In February, Sarnia is bitterly cold: daytime highs average 1 °C, and nights often drop below freezing (−8 °C). Expect around 4.2 hours of sunshine a day. Precipitation falls on about 9 days, totalling 56 mm; on about 5 of them it snows. All in all, February is not an ideal month for a holiday in Sarnia.
Sarnia in February26March6° · 5.3 h
In March, Sarnia is cold: daytime highs average 6 °C, and nights often drop below freezing (−3 °C). Expect around 5.3 hours of sunshine a day. Rain is frequent, with about 10 rainy days and 59 mm in total. Snow falls on about 3 days. All in all, March is not an ideal month for a holiday in Sarnia.
Sarnia in March51April13° · 6.3 h
In April, Sarnia is cool: daytime highs average 13 °C, and nights cool down to about 3 °C. Expect around 6.3 hours of sunshine a day. Rain is frequent, with about 12 rainy days and 82 mm in total. All in all, April is a so-so month for a holiday in Sarnia.
Sarnia in April77May20° · 7.3 h
In May, Sarnia is mild: daytime highs average 20 °C, and nights cool down to about 9 °C. The sun shines for around 7.3 hours a day. Rain is frequent, with about 12 rainy days and 84 mm in total. All in all, May is a good month for a holiday in Sarnia.
Sarnia in May83June25° · 8.5 h
In June, Sarnia is warm: daytime highs average 25 °C, and nights cool down to about 15 °C. The sun shines for around 8.5 hours a day. Rain is frequent, with about 11 rainy days and 86 mm in total. On about 5 days the thermometer climbs to 30 °C or more. All in all, June is an excellent month for a holiday in Sarnia.
Sarnia in June80July28° · 8.9 h
In July, Sarnia is hot: daytime highs average 28 °C, and nights cool down to about 18 °C. The sun shines for around 8.9 hours a day. Rain is frequent, with about 11 rainy days and 76 mm in total. On about 8 days the thermometer climbs to 30 °C or more. All in all, July is an excellent month for a holiday in Sarnia.
Sarnia in July82August27° · 7.5 h
In August, Sarnia is warm: daytime highs average 27 °C, and nights cool down to about 17 °C. The sun shines for around 7.5 hours a day. Rain is frequent, with about 10 rainy days and 70 mm in total. All in all, August is an excellent month for a holiday in Sarnia.
Sarnia in August81September23° · 6.4 h
In September, Sarnia is warm: daytime highs average 23 °C, and nights cool down to about 13 °C. Expect around 6.4 hours of sunshine a day. Rain falls on about 9 days, adding up to 73 mm. All in all, September is an excellent month for a holiday in Sarnia.
Sarnia in September61October16° · 4.7 h
In October, Sarnia is mild: daytime highs average 16 °C, and nights cool down to about 7 °C. Expect around 4.7 hours of sunshine a day. Rain is frequent, with about 11 rainy days and 75 mm in total. All in all, October is a good month for a holiday in Sarnia.
Sarnia in October25November9° · 3.5 h
In November, Sarnia is cold: daytime highs average 9 °C, and nights cool down to about 2 °C. The sun is scarce, with only about 3.5 hours a day. Rain is frequent, with about 9 rainy days and 59 mm in total. Snow falls on about 2 days. All in all, November is not an ideal month for a holiday in Sarnia.
Sarnia in November18December3° · 2.5 h
In December, Sarnia is bitterly cold: daytime highs average 3 °C, and nights often drop below freezing (−4 °C). The sun is scarce, with only about 2.5 hours a day. Precipitation falls on about 10 days, totalling 61 mm; on about 4 of them it snows. All in all, December is not an ideal month for a holiday in Sarnia.
Sarnia in DecemberClimate in detail
Climate through the year
Long-term monthly averages. Tap a month to see its details.
Nights and sleep in Sarnia
How warm the nights get in each month, from the mean night-time low. Tap a month for details.
- Frost below 0°
- Cold 0–8°
- Cool 8–15°
- Pleasant 15–20°
ColdOctober: nights around 7°. The room should be heated. Muggy on about 1 day (dew point 18 °C or more).
The coolest nights are in January (−8°), the warmest in July (18°). Nights are pleasant for sleeping (15 to 20 °C) from June to August. Nights fall below 8 °C on average from October to April, so the room should be heated.
Temperatures through the year
Average daytime high, night-time low and sea temperature per month.
| Month | Score | Day | Night | Sun | Rain days | Rain mm |
|---|---|---|---|---|---|---|
| JanuaryJan | 18 | 0° | −8° | 3.0 h | 10 | 56 |
| FebruaryFeb | 24 | 1° | −8° | 4.2 h | 9 | 56 |
| MarchMar | 26 | 6° | −3° | 5.3 h | 10 | 59 |
| AprilApr | 51 | 13° | 3° | 6.3 h | 12 | 82 |
| MayMay | 77 | 20° | 9° | 7.3 h | 12 | 84 |
| JuneJun | 83 | 25° | 15° | 8.5 h | 11 | 86 |
| JulyJul | 80 | 28° | 18° | 8.9 h | 11 | 76 |
| AugustAug | 82 | 27° | 17° | 7.5 h | 10 | 70 |
| SeptemberSep | 81 | 23° | 13° | 6.4 h | 9 | 73 |
| OctoberOct | 61 | 16° | 7° | 4.7 h | 11 | 75 |
| NovemberNov | 25 | 9° | 2° | 3.5 h | 9 | 59 |
| DecemberDec | 18 | 3° | −4° | 2.5 h | 10 | 61 |
Climate averages 1996–2025 (sunshine partly WMO station normals 1991–2020), not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences
42.98° N, 82.40° W · 185 m · America/Toronto
Sunshine hours in Sarnia
Average hours of bright sunshine per day, next to the length of the day. Tap a month to select it.
In October, the sun shines for about 4.7 of 11.1 hours of daylight in Sarnia, 42 % of the daylight hours.
Sunshine hours: estimated from radiation data (ERA5, 1996–2025) and calibrated against measured station values; no weather station is close enough here. Daylight is the time from sunrise to sunset on the 15th of the month.
Rain in Sarnia: rainy days and rainfall
A rainy day is a day with at least 1 mm of rain or snow; the amount is what falls in the whole month. Tap a month to select it.
In October, Sarnia has about 11 rainy days with 75 mm of rain in total.
UV index in Sarnia
How strong the sun is at noon, month by month, and how quickly unprotected skin burns.
- Clear-sky UV in October
- 3 · moderateAround midday seek shade; use sunscreen, a hat and sunglasses.
The sun is strongest in June (UV 9).
Minutes until sunburn in October
- Very fair skin
- about 40 min
- Fair skin
- about 50 min
- Light brown skin
- about 65 min
- Olive skin
- about 85 min
Rough guide for unprotected skin at noon under a clear sky; clouds lengthen the time, water, sand and snow shorten it. Sunscreen extends the time only partly.
Monthly values: clear-sky noon estimate from the sun's angle, ozone and altitude. UV today: Open-Meteo forecast.
Wind and clouds in Sarnia
How breezy and how cloudy Sarnia is through the year. Tap a month to select it on the whole page.
Wind
Typical daily peak of the wind in km/h: what the afternoon breeze usually reaches, not the gusts.
In October, the wind in Sarnia typically peaks at 21 km/h during the day: Beaufort 4, moderate breeze.
Clouds
Average share of the sky covered by cloud, day and night.
In October, cloud covers on average 60 % of the sky over Sarnia: variable cloud, with about 4.7 hours of sunshine a day.
Wind: mean daily maximum of the hourly wind 10 m above ground (ERA5, 1996–2025). Gusts are stronger, and the model grid of about 28 km smooths out local effects such as capes and valley winds. Clouds: mean total cloud cover of all layers over day and night (ERA5, 1996–2025). Thin high cloud counts as cover even when the sun still shines through.
Heat and humidity in Sarnia
How often the day gets hot in Sarnia (30 °C and more), and in which months heat and humidity come together. Tap a month to select it.
Heat calendar
- pleasant
- some hot or muggy days
- often muggy
- often hot
- hot and muggy
In October, Sarnia has about 0 hot days, with an average daytime high of 16 °C: pleasant. Heat plays no part this month.
Hot days reach at least 30 °C; a month counts as muggy when the mean dew point reaches 18 °C on at least 15 days. Averages from ERA5 and ERA5-Land, 1996–2025. Muggy nights through the year
Snow in Sarnia
When Sarnia is likely to be white: the chance of seeing snow during a week's stay, the days with fresh snow and how much falls. Tap a month to select it.
Snow calendar
- hardly any
- possible
- likely
- very likely
In October, it hardly ever snows in Sarnia.
Snow days bring at least 1 cm of fresh snow. Fresh snow comes from ERA5 snowfall (1996–2025) at the height of the place, not on the slopes above it; the snow chance also weighs whether the snow settles. An estimate from climate averages, not a snow report.
Planning a trip to Sarnia
Weather for your travel dates
Pick your arrival and length of stay, and we sum up the weather to expect.
Sarnia in the school holidays
How the weather suits the usual holiday periods. Dates vary by school and region, so each holiday uses the months it usually falls in.
Sarnia has its best school-holiday weather during the summer holidays (score 81) and its weakest during the Christmas holidays (score 18).
- 43
Easter holidays
Mar – Apr
Fair
- 11 °C by day
- 6.0 h of sun a day
- 11 rainy days a month
Keep in mind: Snow
- 78
May half-term
May – Jun
Good
- 21 °C by day
- 7.5 h of sun a day
- 12 rainy days a month
Good for: Sightseeing & walks
- 81
Summer holidays
Jul – Aug
ExcellentBest holidays
- 27 °C by day
- 8.0 h of sun a day
- 10 rainy days a month
Good for: Sightseeing & walks
- 61
October half-term
Oct
Good
- 16 °C by day
- 4.7 h of sun a day
- 11 rainy days a month
Good for: Sightseeing & walks
- 18
Christmas holidays
Dec – Jan
Poor
- 1 °C by day
- 2.8 h of sun a day
- 10 rainy days a month
Keep in mind: Snow
Based on the climate averages 1996–2025.
Getting there
Flying from
- Nonstop flight
- about 7 h 40 min
- Distance
- 5,930 km
- Time zone
- UTC−4
- Jet lag
- About 3 days (5 h west)
Rule of thumb for flying west: for a few days before, stay up a little later, and get afternoon and evening light at your destination.
Estimated from the straight-line distance: 30 minutes for take-off and landing plus 830 km/h cruising speed.
Compare & alternatives
Sarnia compared
Put Sarnia side by side with another destination.
Sarnia vs Detroit
In October Detroit has the better holiday weather (score 71 vs 61). During the day Detroit is 1 °C warmer than Sarnia.
| in October | Sarnia | Detroit |
|---|---|---|
| Holiday weather score | 61 | 71 |
| Daytime high | 16° | 17° |
| Sunshine | 5 h | 5 h |
| Rainy days | 11 | 9 |
| Best time | May – Sep | May – Oct |
Through the year
Canada in October: the best places
In October, Sarnia ranks 1 among the 31 nearest destinations in this country.
- SarniaThis page16°61
- 2Brantford16°58
- 3Hamilton15°57
- 4St. Catharines16°57
- 5St. Thomas15°55
- 6Burlington15°55
- 7Oakville15°55
- 8Niagara Falls16°55
Near Sarnia
Other destinations close by.
Places with a climate like Sarnia
Destinations whose weather through the year is closest to Sarnia's – good alternatives.
Frequently asked questions about Sarnia
When is the best time to visit Sarnia?
The best time to visit Sarnia is from May to September. That is when the holiday weather score, which combines temperature, sea, sunshine and rain, is highest.
What is the warmest month in Sarnia?
July is the warmest month, with average highs of 28 °C and nights around 18 °C. January is the coolest month at 0 °C.
When does it rain most in Sarnia?
The wettest month is June with 86 mm of precipitation. The driest month is February with 56 mm.
How many hours of sunshine does Sarnia get?
Sarnia gets around 2,070 hours of sunshine a year. The sunniest month is July with 8.9 hours a day; in December there are 2.5 hours a day.
What time zone is Sarnia in?
Sarnia is on UTC−5 in January and UTC−4 in July.
How long is the flight from London to Sarnia?
A nonstop flight from London to Sarnia takes about 7 h 40 min, for a straight-line distance of about 5,930 km.
Which school holidays are best for Sarnia?
Sarnia has its best school-holiday weather during the summer holidays (score 81) and its weakest during the Christmas holidays (score 18). Holiday ratings (0–100): Easter holidays 43, May half-term 78, summer holidays 81, October half-term 61, Christmas holidays 18.