Grosseto weather in September

In September, Grosseto sees average daytime highs of 25°C and overnight lows near 19°C, with 76 mm of rain across 7.6 wet days and about 12.3 hours of daylight. It is the 4th-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 26°C in the first days to 23°C by the end. The sky is clear or mostly clear about 58% of the time in September, and the air most often feels humid.

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 Grosseto's 4th-clearest and 8th-windiest month. For the whole year in context, see Grosseto's year-round climate.

Daytime high
25°
4th warmest
Overnight low
19°
10th coldest
Rainfall
76 mm
7.6 wet days
Daylight
12 h 18 min
6:01 AM – 6:18 PM
Cloud cover
39%
4th clearest
Wind
11 km/h
8th windiest
Solar energy
4.61 kWh/m²
Travel score
7.5
out of 10
Air quality
Good
PM2.5 9.3 µg/m³ · 2019

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 26°C in the first days to 23°C by the end.

A typical September day in Grosseto reaches about 25°C in the afternoon and slips back to 19°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 22°C and 27°C. Set against its neighbours, September runs about 4°C cooler than August and about 4°C warmer than October.

10°15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12720
22720
32620
42620
52620
62620
72620
82619
92619
102519
112519
122519
132519
142519
152519
162419
172418
182418
192418
202418
212418
222418
232318
242318
252318
262317
272317
282317
292317
302317

Grosseto weather by month

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

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan12° / 598.39.23.2
Feb12° / 587.910.33.5
Mar14° / 537.611.64.7
Apr17° / 11°538.513.15.8
May21° / 15°42714.47.2
Jun25° / 18°264.515.18.2
Jul28° / 21°152.414.88.0
Aug28° / 21°213.213.77.5
Sep25° / 19°767.612.37.5
Oct20° / 15°1049.910.86.6
Nov16° / 11°12212.29.64.8
Dec13° / 82108.93.5

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 58% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 15% of September, with mostly cloudy or overcast conditions the remaining 27%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
18317
28119
38119
48119
58020
67822
77822
87723
97624
107525
117426
127426
137228
147228
157129
167129
177030
187030
196931
206931
216931
226931
236931
246931
256832
266832
276832
286733
296832
306832

Chance of precipitation in September

Any precipitation

Grosseto gets around 76 mm of rain over 7.6 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 26% and peaks near 32% on the wettest days. The odds climb toward the end of the month.

0%10%20%30%40%151015202530
Rain chance (%)
118
218
319
419
520
621
721
822
923
1024
1124
1225
1326
1426
1527
1628
1728
1829
1929
2029
2130
2230
2330
2430
2530
2630
2731
2831
2931
3032

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

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

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1814293514
2815303412
3915313411
4101631339
5101732338
6111732337
7111832336
8121832335
9121832335
10121932334
11121932334
12131931334
13131931333
14132031333
15142031323
16142131323
17142231313
18152231293
19162331282
20172431272
21172431252
22182532242
23192532222
24192633211
25192634191
26202734181
27202835171
28212835161
29212935150
30213035140

Wind in September

Winds average 11 km/h in September.

Across September, daily wind ranges from about 10 km/h on the calmest days to 12 km/h at its breeziest. It stays fairly steady from day to day.

051015151015202530
Wind speed (km/h)Feels
110calm
210calm
310calm
411calm
511calm
611calm
711calm
811calm
911calm
1011calm
1111calm
1211calm
1311calm
1411calm
1511calm
1611calm
1711calm
1811calm
1911calm
2011calm
2111calm
2211calm
2311calm
2411calm
2511calm
2611calm
2711calm
2811calm
2912calm
3012calm

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 5:45 AM to 6:17 AM, and sunset from 6:46 PM to 5:53 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.05:456:46
213.05:466:44
312.95:476:42
412.95:486:41
512.85:496:39
612.85:506:37
712.75:516:35
812.75:526:33
912.65:546:31
1012.65:556:30
1112.55:566:28
1212.55:576:26
1312.45:586:24
1412.45:596:22
1512.36:006:20
1612.36:016:18
1712.26:026:17
1812.26:046:15
1912.16:056:13
2012.16:066:11
2112.06:076:09
2212.06:086:07
2311.96:096:05
2411.96:106:04
2511.86:116:02
2611.86:136:00
2711.76:145:58
2811.76:155:56
2911.66:165:54
3011.66:175:53

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 4.61 kWh/m².

For context, solar energy here swings from a low near 1.59 kWh/m² to a high of 7.16 kWh/m² in July across the year — September's 4.61 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
15.4Bright
25.4Bright
35.3Bright
45.3Bright
55.2Bright
65.1Bright
75.1Bright
85.0Bright
94.9Bright
104.9Bright
114.8Bright
124.8Bright
134.7Bright
144.7Bright
154.6Bright
164.5Bright
174.5Bright
184.4Bright
194.4Bright
204.3Bright
214.3Bright
224.2Bright
234.2Bright
244.1Bright
254.1Bright
264.0Bright
274.0Moderate
283.9Moderate
293.9Moderate
303.8Moderate
Planning a trip in September

Hazard calendar for Grosseto

In seasonPeak

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

Grosseto's rainy season runs September–February, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is September a good time to visit Grosseto?

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

7.5
Sightseeing
3rd-best month of the year
6.5
Beach & pool
4th-best month of the year

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

What to pack for Grosseto in September

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

In September, Grosseto sees daytime highs around 25°C and nights near 19°C. Worth packing: light clothes and sun protection. About 8 days see rain.

light clothessun protection

Sea temperature near Grosseto in September

The nearest coast averages about 23°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 15 km away) is warmest in August at about 25°C and coldest in February near 14°C.

It's comfortable for a long swim from Jun 3 to Oct 28 — about 4.9 months when the water holds above 20°C.

15°20°25°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan15Bracing
Feb14Bracing
Mar14Bracing
Apr15Cool
May18Cool
Jun22Refreshing
Jul24Warm
Aug25Warm
Sep23Refreshing
Oct21Refreshing
Nov19Cool
Dec16Cool

UV index in Grosseto 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 Grosseto peaks around July 14 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 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 highHighModerateLowJul 14UV 9Dec 23UV 1
UV index (midday)Level
Jan1Low
Feb3Moderate
Mar5Moderate
Apr5High
May6High
Jun8Very high
Jul9Very high
Aug7Very high
Sep5High
Oct3Moderate
Nov2Moderate
Dec1Low
Location & terrain

Where is Grosseto?

Grosseto sits at 42.8°N, 11.1°E, 10 m above sea level, in Italy. The nearest listed city is Follonica, 34 km away.

Colle di Val d'ElsaCecinaPoggibonsiRosignano Solvay-CastiglioncelloViterbo

Topography around Grosseto

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

Within 3 km, the terrain around Grosseto has only modest variations in elevation — a maximum elevation change of 21 m around an average of 9 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 562 m; within 80 km, very significant variations in elevation — a maximum elevation change of 1,724 m.

The land around Grosseto is covered by cropland (38%) and artificial surfaces (31%) within 3 km, cropland (36%), trees (28%) and grassland (23%) within 16 km, and water (40%) and trees (33%) within 80 km.

3 km
21 m
16 km
562 m
80 km
1,724 m
treesshrubsgrasslandcroplandartificial surfaceswaterwetland
September weather nearby: Follonica 34 km · Piombino 51 km · Siena 64 km · Colle di Val d'Elsa 73 km · Cecina 77 km · Poggibonsi 79 km · Rosignano Solvay-Castiglioncello 89 km · Viterbo 90 km

Italy travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type C / F / L
230 V · 50 Hz
Prices
≈ 69% of US
price level, 2025
GDP per capita
$43,309
2025
Happiness
6.6 / 10
World Happiness, 2025
Safe drinking water
97%
of population, 2024
Homicide rate
0.6
per 100k, 2023
Road deaths
5.3
per 100k/yr, 2019
Income group
High
World Bank
English
Moderate
EF EPI 513
Religion
Christian 81%unaffiliated 13%Muslim 5%other 1%

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 Grosseto (42.763°, 11.1094°, elevation 10 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).