Hamilton weather in September

In September, Hamilton sees average daytime highs of 21°C and overnight lows near 14°C, with 77 mm of rain across 9.3 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 24°C in the first days to 19°C by the end. The sky is clear or mostly clear about 34% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 hours at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Hamilton's 3rd-clearest and 8th-windiest month. For the whole year in context, see Hamilton's year-round climate.

Daytime high
21°
4th warmest
Overnight low
14°
9th coldest
Rainfall
77 mm
9.3 wet days
Daylight
12 h 18 min
6:05 AM – 6:22 PM
Cloud cover
55%
3rd clearest
Wind
13 km/h
8th windiest
Solar energy
4.15 kWh/m²
Travel score
6.7
out of 10

Hamilton is city in Ontario, Canada.

Air quality
Good
PM2.5 8.5 µg/m³ · 2019
Founded
1846

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 24°C in the first days to 19°C by the end.

A typical September day in Hamilton reaches about 21°C in the afternoon and slips back to 14°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 16°C and 26°C. Set against its neighbours, September runs about 4°C cooler than August and about 7°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12416
22416
32416
42316
52316
62316
72315
82315
92315
102315
112215
122215
132214
142214
152214
162114
172114
182113
192113
202113
212013
222013
232012
242012
251912
261912
271912
281911
291911
301811

How September really feels in Hamilton

Once humidity and wind are folded in, September 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

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

Hamilton weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan-1° / -7°7111.48.19.20.0
Feb / -7°568.56.410.20.0
Mar / -3°699.94.511.60.2
Apr11° / 9411.51.813.22.4
May17° / 8311.2014.55.1
Jun22° / 15°8611.6015.16.5
Jul26° / 18°7710014.96.8
Aug25° / 18°699.4013.87.0
Sep21° / 14°779.3012.36.7
Oct15° / 8511010.84.2
Nov / 7910.32.19.51.2
Dec / -3°7110.55.88.90.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 34% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 18% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15743
25644
35644
45545
55545
65545
75446
85446
95446
105446
115347
125347
135248
145248
155248
165248
175248
185248
195248
205149
215050
225050
235050
245050
254951
264753
274753
284654
294654
304654

Chance of precipitation in September

Any precipitation

Hamilton gets around 77 mm of rain over 9.3 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 31% and peaks near 37% on the wettest days.

0%10%20%30%40%50%151015202530
Rain chance (%)
129
230
330
430
531
631
731
831
931
1031
1131
1230
1330
1430
1529
1629
1729
1829
1929
2029
2130
2230
2331
2432
2533
2634
2735
2836
2937
3037

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the dry band about 48% of days. Sticky, muggy-or-worse air turns up on roughly 11% of them.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1272624203
2282624193
3302623183
4312623172
5332622162
6342622162
7362622152
8372621142
9392521132
10402521131
11422521121
12432421111
13442420101
14462420101
1547242090
1649241980
1750231980
1852231870
1952231870
2055221760
2156221660
2258221550
2360211450
2462211340
2562211340
2664201240
2766201130
2867201030
2968191030
306919930

Wind in September

Winds average 13 km/h in September.

Across September, daily wind ranges from about 12 km/h on the calmest days to 14 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
112calm
212calm
312calm
412calm
512light breeze
612light breeze
712light breeze
812light breeze
912light breeze
1012light breeze
1112light breeze
1212light breeze
1313light breeze
1413light breeze
1513light breeze
1613light breeze
1713light breeze
1813light breeze
1913light breeze
2013light breeze
2113light breeze
2213light breeze
2313light breeze
2413light breeze
2513light breeze
2614light breeze
2714light breeze
2814light breeze
2914light breeze
3014light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 hours at the start of September to 11 h 36 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 84 minutes over September. Sunrise moves from 5:48 AM to 6:21 AM, and sunset from 6:50 PM to 5:56 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:486:50
213.05:496:48
312.95:506:47
412.95:516:45
512.85:526:43
612.85:546:41
712.75:556:39
812.75:566:37
912.65:576:36
1012.65:586:34
1112.55:596:32
1212.56:006:30
1312.46:026:28
1412.46:036:26
1512.36:046:24
1612.36:056:22
1712.26:066:21
1812.26:076:19
1912.16:086:17
2012.16:106:15
2112.06:116:13
2212.06:126:11
2311.96:136:09
2411.96:146:07
2511.86:156:05
2611.86:176:04
2711.76:186:02
2811.76:196:00
2911.66:205:58
3011.66:215:56

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.15 kWh/m².

For context, solar energy here swings from a low near 1.32 kWh/m² to a high of 6.31 kWh/m² in June across the year — September's 4.15 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.8Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.5Bright
94.4Bright
104.4Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.2Bright
164.1Bright
174.1Bright
184.0Bright
194.0Bright
204.0Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.5Moderate
303.5Moderate
Planning a trip in September

Is September a good time to visit Hamilton?

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

6.7
Sightseeing
3rd-best month of the year
4.3
Beach & pool
4th-best month of the year

September is a reasonable time to visit Hamilton for sightseeing.

What to pack for Hamilton in September

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

In September, Hamilton sees daytime highs around 21°C and nights near 14°C. Worth packing: rain gear. About 9 days see rain.

rain gear

Sea temperature near Hamilton in September

The nearest coast averages about 19°C in September — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 23 km away) is warmest in August at about 21°C and coldest in February near 3°C.

It's comfortable for a long swim from Jul 22 to Sep 1 — about 1.4 months when the water holds above 20°C.

0°10°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarm
Sea temperature (°C)Comfort
Jan4Bracing
Feb3Bracing
Mar3Bracing
Apr4Bracing
May8Bracing
Jun15Cool
Jul20Cool
Aug21Refreshing
Sep19Cool
Oct13Bracing
Nov8Bracing
Dec5Bracing

UV index in Hamilton in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 5 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Hamilton peaks around June 22 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 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 22UV 8Dec 22UV 1
UV index (midday)Level
Jan1Low
Feb2Moderate
Mar4Moderate
Apr5High
May6High
Jun8Very high
Jul8Very high
Aug7High
Sep5High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Hamilton?

Hamilton sits at 43.3°N, 79.8°W, 95 m above sea level, in Canada. The nearest listed city is Stoney Creek, 8.0 km away.

Topography around Hamilton

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

Within 3 km, the terrain around Hamilton has only modest variations in elevation — a maximum elevation change of 144 m around an average of 125 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 235 m; within 80 km, significant variations in elevation — a maximum elevation change of 457 m.

The land around Hamilton is covered by artificial surfaces (66%) and trees (25%) within 3 km, trees (28%) and cropland (20%) within 16 km, and cropland (31%), water (29%) and trees (22%) within 80 km.

3 km
144 m
16 km
235 m
80 km
457 m
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Stoney Creek 8.0 km · Waterdown 10 km · Ancaster 12 km · Burlington 15 km · Grimsby 24 km · Oakville 26 km · Milton 30 km · Brantford 36 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 Hamilton (43.2501°, -79.8496°, elevation 95 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).