Alliston weather in August

In August, Alliston sees average daytime highs of 25°C and overnight lows near 14°C, with 76 mm of rain across 9.8 wet days and about 13.8 hours of daylight. It is the 2nd-warmest and 3rd-wettest month of the year here.

Highs ease over the month, from about 25°C in the first days to 24°C by the end. The sky is clear or mostly clear about 33% of the time in August, and the air most often feels dry.

Daylight stretches from about 14 h 30 min at the start of August to 13 h 06 min by month's end. Set against the rest of the year, August is Alliston's 2nd-clearest and 12th-windiest month. For the whole year in context, see Alliston's year-round climate.

Daytime high
25°
2nd warmest
Overnight low
14°
11th coldest
Rainfall
76 mm
9.8 wet days
Daylight
13 h 48 min
5:28 AM – 7:19 PM
Cloud cover
56%
2nd clearest
Wind
10 km/h
12th windiest
Solar energy
5.29 kWh/m²
Travel score
7.0
out of 10

Alliston is settlement in Simcoe County, Ontario, Canada.

Founded
1874

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 25°C in the first days to 24°C by the end.

A typical August day in Alliston reaches about 25°C in the afternoon and slips back to 14°C overnight — a 10°C spread between the day's warmth and the night's chill. On most days the high lands between 20°C and 29°C. Set against its neighbours, August runs about 1°C cooler than July and about 4°C warmer than September.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12515
22515
32515
42515
52515
62515
72515
82515
92515
102515
112515
122515
132515
142515
152514
162514
172514
182514
192514
202414
212414
222414
232414
242414
252414
262414
272414
282414
292413
302413
312413

How August really feels in Alliston

Once humidity and wind are folded in, August averages 0 days that feel above 32°C and 0 that feel at or below 0°C — the comfort signal a plain temperature reading hides.

Days feeling ≥ 32°C
0
heat index over the day's high
Days feeling ≤ C
0
wind chill below the day's low

August sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Alliston weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 3rd-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-3° / -11°5610.410.29.10.0
Feb-2° / -11°468.47.610.20.0
Mar / -5°5410.16.111.60.2
Apr11° / 7410.82.713.22.8
May18° / 8010.7014.55.7
Jun23° / 13°8310.9015.26.7
Jul26° / 15°7510.60156.7
Aug25° / 14°769.8013.87.0
Sep21° / 10°719.7012.36.5
Oct13° / 7311.20.410.83.6
Nov / -1°6710.74.19.40.6
Dec / -7°5710.998.70.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 33% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 20% of August, with mostly cloudy or overcast conditions the remaining 46%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15347
25347
35347
45347
55347
65347
75347
85347
95446
105446
115347
125347
135347
145347
155347
165446
175347
185347
195347
205446
215347
225347
235446
245446
255446
265446
275446
285545
295545
305545
315545

Chance of precipitation in August

Any precipitation

Alliston gets around 76 mm of rain over 9.8 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 32% and peaks near 35% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
135
235
335
435
535
635
734
834
934
1034
1133
1233
1333
1433
1533
1632
1732
1832
1931
2031
2131
2230
2330
2429
2529
2629
2729
2828
2929
3029
3129

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

Most of August feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, August lands in the dry band about 32% of days. Sticky, muggy-or-worse air turns up on roughly 12% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1253427131
2253427131
3253427131
4263327131
5263327131
6273227131
7273227131
8283127131
9293127131
10303027121
11303027121
12312927121
13322927120
14322927120
15322927120
16332927110
17332927110
18332926110
19342926110
20342926110
21342926110
22342925110
23352925110
24352925110
25362925100
26372924100
27372924100
28382923100
29392922100
30402921100
31412920100

Wind in August

Winds average 10 km/h in August, the calmest month.

Across August, daily wind ranges from about 10 km/h on the calmest days to 10 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (km/h)Feels
110calm
210calm
310calm
410calm
510calm
610calm
710calm
810calm
910calm
1010calm
1110calm
1210calm
1310calm
1410calm
1510calm
1610calm
1710calm
1810calm
1910calm
2010calm
2110calm
2210calm
2310calm
2410calm
2510calm
2610calm
2710calm
2810calm
2910calm
3010calm
3110calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 30 min at the start of August to 13 h 06 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over August. Sunrise moves from 5:11 AM to 5:46 AM, and sunset from 7:40 PM to 6:53 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.55:117:40
214.45:127:39
314.45:137:38
414.45:147:36
514.35:157:35
614.35:177:34
714.25:187:32
814.25:197:31
914.25:207:30
1014.15:217:28
1114.15:227:27
1214.05:237:25
1314.05:257:24
1413.95:267:22
1513.95:277:21
1613.85:287:19
1713.85:297:17
1813.85:307:16
1913.75:327:14
2013.75:337:12
2113.65:347:11
2213.65:357:09
2313.55:367:07
2413.55:387:06
2513.45:397:04
2613.45:407:02
2713.35:417:00
2813.35:426:59
2913.25:436:57
3013.25:456:55
3113.15:466:53

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.29 kWh/m².

For context, solar energy here swings from a low near 1.24 kWh/m² to a high of 6.3 kWh/m² in June across the year — August's 5.29 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.8Bright
25.7Bright
35.7Bright
45.7Bright
55.7Bright
65.6Bright
75.6Bright
85.6Bright
95.5Bright
105.5Bright
115.5Bright
125.4Bright
135.4Bright
145.4Bright
155.3Bright
165.3Bright
175.3Bright
185.2Bright
195.2Bright
205.2Bright
215.1Bright
225.1Bright
235.1Bright
245.0Bright
255.0Bright
265.0Bright
274.9Bright
284.9Bright
294.8Bright
304.8Bright
314.7Bright
Planning a trip in August

Is August a good time to visit Alliston?

Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.0
Sightseeing
1st-best month of the year
6.1
Beach & pool
2nd-best month of the year

August is one of the better times to visit Alliston for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Alliston in August

From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In August, Alliston sees daytime highs around 25°C and nights near 14°C. Worth packing: light clothes, rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

Sea temperature near Alliston in August

The nearest coast averages about 21°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 57 km away) is warmest in August at about 21°C and coldest in March near 1°C.

It's comfortable for a long swim from Aug 9 to Aug 24 — about 0.5 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°C)Comfort
Jan3Bracing
Feb2Bracing
Mar1Bracing
Apr2Bracing
May5Bracing
Jun11Bracing
Jul19Cool
Aug21Refreshing
Sep19Cool
Oct13Bracing
Nov9Bracing
Dec6Bracing

UV index in Alliston in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Alliston peaks around June 23 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJun 23UV 8Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5High
May6High
Jun8Very high
Jul8Very high
Aug7High
Sep5High
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Alliston in August

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.

Air quality in Alliston is worst in May — around 19 µg/m³ PM2.5 (moderate), about 2.1× the cleanest month (November, 9 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodMay 2019 µg/m³Nov 239 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb14Moderate
Mar16Moderate
Apr17Moderate
May19Moderate
Jun18Moderate
Jul18Moderate
Aug16Moderate
Sep14Moderate
Oct10Good
Nov9Good
Dec9Good
Location & terrain

Where is Alliston?

Alliston sits at 44.2°N, 79.9°W, 223 m above sea level, in Canada. The nearest listed city is Innisfil, 24 km away.

Topography around Alliston

How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Alliston.

Within 3 km, the terrain around Alliston has only modest variations in elevation — a maximum elevation change of 71 m around an average of 227 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 266 m; within 80 km, significant variations in elevation — a maximum elevation change of 471 m.

The land around Alliston is covered by cropland (37%), grassland (24%) and trees (20%) within 3 km, cropland (42%), trees (35%) and grassland (21%) within 16 km, and trees (37%) and cropland (29%) within 80 km.

3 km
71 m
16 km
266 m
80 km
471 m
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Innisfil 24 km · Bolton 32 km · Orangeville 32 km · Barrie 32 km · Caledon 33 km · Keswick 34 km · Newmarket 34 km · East Gwillimbury 35 km

Canada travel facts

Travel advisory
Level 1
Exercise Normal Precautions
Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 83% of US
price level, 2025
GDP per capita
$55,698
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
97%
of population, 2024
Homicide rate
2
per 100k, 2023
Road deaths
5.3
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 53%none 35%Muslim 5%Hindu 2%

Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.

Data sources

Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Alliston (44.1501°, -79.8663°, elevation 223 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).