Waterville weather in September

In September, Waterville sees average daytime highs of 68°F and overnight lows near 53°F, with 3.3 in of rain across 8.2 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 73°F in the first days to 64°F by the end. The sky is clear or mostly clear about 38% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 06 min at the start of September to 11 h 36 min by month's end. Set against the rest of the year, September is Waterville's 1st-clearest and 9th-windiest month. For the whole year in context, see Waterville's year-round climate.

Daytime high
68°
4th warmest
Overnight low
53°
9th coldest
Rainfall
3.3 in
8.2 wet days
Daylight
12 h 18 min
5:24 AM – 5:42 PM
Cloud cover
55%
1st clearest
Wind
6 mph
9th windiest
Solar energy
4.07 kWh/m²
Travel score
6.6
out of 10

Waterville is city in Maine, United States.

Density
447/km²
people per km²
Founded
1802

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 73°F in the first days to 64°F by the end.

A typical September day in Waterville reaches about 68°F in the afternoon and slips back to 53°F overnight — a 15°F spread between the day's warmth and the night's chill. On most days the high lands between 60°F and 77°F. Set against its neighbours, September runs about 8°F cooler than August and about 12°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
17358
27357
37357
47357
57256
67256
77156
87155
97155
107155
117055
127054
136954
146953
156953
166853
176852
186852
196752
206751
216651
226651
236650
246550
256550
266449
276449
286449
296348
306348

How September really feels in Waterville

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
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.

Waterville 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 (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan28° / 12°3.18.96.890.0
Feb30° / 14°2.98.37.210.10.0
Mar38° / 23°3.610.26.111.60.1
Apr51° / 36°3.810.62.613.22.3
May62° / 46°3.2110.214.65.1
Jun71° / 56°3.811015.36.4
Jul77° / 62°3.19.90156.7
Aug76° / 61°2.99.3013.97.1
Sep68° / 53°3.38.2012.36.6
Oct56° / 42°4.410.10.410.73.9
Nov44° / 31°3.59.52.39.40.8
Dec33° / 20°4.010.76.98.70.0

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 38% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
15545
25545
35446
45446
55347
65347
75347
85347
95347
105347
115347
125347
135248
145347
155248
165347
175248
185248
195248
205149
215149
225050
235050
245050
255050
265050
275050
285050
295050
305050

Chance of precipitation in September

Any precipitation

Waterville gets around 3.3 in of rain over 8.2 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 28% and peaks near 30% on the wettest days.

0%10%20%30%40%151015202530
Rain chance (%)
126
226
327
427
527
628
728
828
928
1028
1128
1228
1328
1428
1527
1627
1727
1827
1927
2027
2127
2227
2327
2427
2528
2628
2729
2829
2930
3030

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 58% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)
137292310
238292310
34028229
44128229
54328218
64427217
74627217
84726216
94925216
105124205
115224204
125323204
135622193
145622193
155821183
165921182
176120172
186220162
196419161
206519151
216718141
226818131
236917131
247017121
257216111
267316101
27751591
28761581
29781471
30801361

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
236calm
246calm
256calm
267calm
277calm
287calm
297calm
307calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 06 min 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 90 minutes over September. Sunrise moves from 5:06 AM to 5:41 AM, and sunset from 6:11 PM to 5:15 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.15:066:11
213.05:076:09
313.05:086:07
412.95:096:05
512.95:106:03
612.85:126:01
712.85:135:59
812.75:145:58
912.75:155:56
1012.65:165:54
1112.65:185:52
1212.55:195:50
1312.55:205:48
1412.45:215:46
1512.45:235:44
1612.35:245:42
1712.35:255:40
1812.25:265:38
1912.15:275:36
2012.15:295:34
2112.05:305:32
2212.05:315:30
2311.95:325:28
2411.95:335:26
2511.85:355:24
2611.85:365:22
2711.75:375:21
2811.75:385:19
2911.65:405:17
3011.65:415:15

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.07 kWh/m².

For context, solar energy here swings from a low near 1.45 kWh/m² to a high of 5.8 kWh/m² in July across the year — September's 4.07 kWh/m² falls in the middle.

024151015202530
Solar energy (kWh/m²)Level
14.7Bright
24.7Bright
34.7Bright
44.6Bright
54.6Bright
64.5Bright
74.5Bright
84.4Bright
94.4Bright
104.3Bright
114.3Bright
124.3Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Moderate
193.9Moderate
203.9Moderate
213.8Moderate
223.8Moderate
233.7Moderate
243.7Moderate
253.6Moderate
263.6Moderate
273.5Moderate
283.5Moderate
293.4Moderate
303.4Moderate
Planning a trip in September

Hazard calendar for Waterville

In seasonPeak

In September, Waterville sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Waterville sits in the Atlantic hurricane belt; the season peaks August–October.

Atlantic hurricane
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Waterville?

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

6.6
Sightseeing
3rd-best month of the year
3.6
Beach & pool
4th-best month of the year

September is a reasonable time to visit Waterville for sightseeing.

What to pack for Waterville in September

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

In September, Waterville sees daytime highs around 68°F and nights near 53°F. Worth packing: rain gear. About 8 days see rain.

rain gear

Sea temperature near Waterville in September

The nearest coast averages about 57°F 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 39 mi away) is warmest in August at about 58°F and coldest in February near 35°F.

The water stays below 68°F all year — cool enough that most swimmers want a wetsuit.

30°40°50°60°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°F)Comfort
Jan39Bracing
Feb35Bracing
Mar35Bracing
Apr40Bracing
May46Bracing
Jun52Bracing
Jul57Bracing
Aug58Bracing
Sep57Bracing
Oct54Bracing
Nov49Bracing
Dec44Bracing

UV index in Waterville 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 Waterville peaks around July 13 at about 7 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 21 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateModerateLowJul 13UV 7Dec 21UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar4Moderate
Apr5Moderate
May7High
Jun6High
Jul8Very high
Aug4Moderate
Sep5High
Oct3Moderate
Nov2Low
Dec1Low
Location & terrain

Where is Waterville?

Waterville sits at 44.6°N, 69.6°W, 108 ft above sea level, in United States. The nearest listed city is Augusta, 18 mi away.

Topography around Waterville

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Waterville.

Within 2 miles, the terrain around Waterville has only modest variations in elevation — a maximum elevation change of 394 ft around an average of 157 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 696 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 4,298 ft.

The land around Waterville is covered by trees (60%) within 2 miles, trees (72%) within 10 miles, and trees (83%) within 50 miles.

2 miles
394 ft
10 miles
696 ft
50 miles
4,298 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Augusta 18 mi · Lewiston 42 mi · Auburn 43 mi · Bangor 45 mi · Brunswick 47 mi · Portland 69 mi · South Portland 70 mi · Westbrook 71 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 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 Waterville (44.552°, -69.6317°, elevation 108 ft), 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).