San Martin weather in September

In September, San Martin sees average daytime highs of 27°C and overnight lows near 17°C, with 2 mm of rain across 0.6 wet days and about 12 hours of daylight. It is the 10th-warmest and 10th-wettest month of the year here.

Day-to-day highs hold fairly steady near 27°C through the month. The sky is clear or mostly clear about 52% of the time in September, and the air most often feels comfortable.

Daylight stretches from about 11 h 54 min at the start of September to 12 hours by month's end. Set against the rest of the year, September is San Martin's 4th-clearest and 1st-windiest month. For the whole year in context, see San Martin's year-round climate.

Daytime high
27°
10th warmest
Overnight low
17°
2nd coldest
Rainfall
2 mm
0.6 wet days
Daylight
12 hours
6:18 AM – 6:16 PM
Cloud cover
43%
4th clearest
Wind
13 km/h
1st windiest
Solar energy
6.53 kWh/m²
Travel score
8.3
out of 10

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 27°C through the month.

A typical September day in San Martin reaches about 27°C in the afternoon and slips back to 17°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 25°C and 28°C. Set against its neighbours, September runs on par with August and about 1°C cooler than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12617
22617
32617
42617
52617
62617
72617
82617
92617
102617
112617
122617
132717
142717
152717
162717
172717
182717
192717
202717
212717
222717
232717
242717
252717
262717
272718
282718
292718
302718

How September really feels in San Martin

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.

San Martin weather by month

How September compares with the rest of the year at a glance. September is the 10th-warmest and 10th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysDaylight (hours)Travel score
Jan31° / 22°375.512.34.6
Feb32° / 23°629.412.23.7
Mar32° / 23°10711.2123.5
Apr32° / 22°386.411.94.5
May30° / 20°72.311.86.0
Jun28° / 19°30.911.77.9
Jul26° / 18°10.211.78.5
Aug26° / 17°00.111.88.8
Sep27° / 17°20.6128.3
Oct27° / 18°41.512.17.8
Nov28° / 18°82.212.27.0
Dec30° / 20°214.912.35.7

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 52% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 19% of September, with mostly cloudy or overcast conditions the remaining 29%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
17921
27921
37822
47723
57624
67624
77525
87426
97327
107327
117228
127129
137129
147129
157030
167030
176931
186931
196832
206832
216832
226832
236832
246832
256733
266733
276733
286634
296634
306634

Chance of precipitation in September

Any precipitation

San Martin gets around 2 mm of rain over 0.6 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 2% and peaks near 3% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
11
21
31
41
51
61
71
81
92
102
112
122
132
142
152
162
172
182
192
203
213
223
232
242
252
262
272
282
292
302

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, September lands in the comfortable band about 62% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)
164333
264333
363343
463343
563343
663343
763343
863343
962353
1062353
1162353
1262353
1362353
1462353
1562353
1662353
1762353
1862353
1962353
2062353
2162353
2262353
2362353
2462353
2562353
2662353
2762353
2862353
2961363
3061363

Wind in September

Winds average 13 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 13 km/h on the calmest days to 13 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
113light breeze
213light breeze
313light breeze
413light breeze
513light breeze
613light breeze
713light breeze
813light breeze
913light breeze
1013light breeze
1113light breeze
1213light 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
2613light breeze
2713light breeze
2813light breeze
2913light breeze
3013light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 11 h 54 min at the start of September to 12 hours by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 6 minutes over September. Sunrise moves from 6:25 AM to 6:11 AM, and sunset from 6:19 PM to 6:13 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:256:19
211.96:256:19
311.96:246:19
411.96:246:19
511.96:236:19
611.96:236:18
711.96:226:18
811.96:226:18
911.96:216:18
1011.96:216:18
1111.96:206:17
1212.06:206:17
1312.06:196:17
1412.06:196:17
1512.06:186:16
1612.06:186:16
1712.06:176:16
1812.06:176:16
1912.06:166:15
2012.06:166:15
2112.06:156:15
2212.06:156:15
2312.06:146:15
2412.06:146:14
2512.06:136:14
2612.06:136:14
2712.06:126:14
2812.06:126:14
2912.06:116:13
3012.06:116:13

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.53 kWh/m².

For context, solar energy here swings from a low near 5.39 kWh/m² to a high of 6.68 kWh/m² in October across the year — September's 6.53 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.3Intense
26.4Intense
36.4Intense
46.4Intense
56.4Intense
66.4Intense
76.4Intense
86.4Intense
96.5Intense
106.5Intense
116.5Intense
126.5Intense
136.5Intense
146.5Intense
156.5Intense
166.6Intense
176.6Intense
186.6Intense
196.6Intense
206.6Intense
216.6Intense
226.6Intense
236.6Intense
246.6Intense
256.6Intense
266.6Intense
276.6Intense
286.6Intense
296.6Intense
306.7Intense
Planning a trip in September

Is September a good time to visit San Martin?

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

8.3
Sightseeing
3rd-best month of the year
8.2
Beach & pool
4th-best month of the year

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

What to pack for San Martin in September

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

In September, San Martin sees daytime highs around 27°C and nights near 17°C. Pack sun protection. Worth having: light clothes.

sun protectionlight clothes

Sea temperature near San Martin in September

The nearest coast averages about 18°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 54 km away) is warmest in February at about 23°C and coldest in September near 18°C.

It's comfortable for a long swim from Dec 25 to May 15 — about 4.7 months when the water holds above 20°C.

16°18°20°22°24°JanFebMarAprMayJunJulAugSepOctNovDeccoolrefreshingwarmcomfortable to swim
Sea temperature (°C)Comfort
Jan21Refreshing
Feb23Refreshing
Mar23Refreshing
Apr21Refreshing
May20Refreshing
Jun19Cool
Jul18Cool
Aug18Cool
Sep18Cool
Oct18Cool
Nov19Cool
Dec20Cool

UV index in San Martin in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 12 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in San Martin peaks around February 19 at about 16 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near June 22 at about 10 (extreme).

The index reaches 3 or more — the level where the WHO recommends sun protection — every month of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeFeb 19UV 16Jun 22UV 10
UV index (midday)Level
Jan15Extreme
Feb16Extreme
Mar16Extreme
Apr13Extreme
May12Extreme
Jun10Very high
Jul10Extreme
Aug11Extreme
Sep12Extreme
Oct14Extreme
Nov13Extreme
Dec13Extreme
Location & terrain

Where is San Martin?

San Martin sits at 5.2°S, 80.7°W, 35 m above sea level, in Peru. The nearest listed city is Piura, 1.0 km away.

Topography around San Martin

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

Within 3 km, the terrain around San Martin has only modest variations in elevation — a maximum elevation change of 26 m around an average of 35 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 127 m; within 80 km, very significant variations in elevation — a maximum elevation change of 2,178 m.

The land around San Martin is covered by artificial surfaces (57%) and bare terrain (25%) within 3 km, bare terrain (58%) within 16 km, and bare terrain (36%) and shrubs (26%) within 80 km.

3 km
26 m
16 km
127 m
80 km
2,178 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Piura 1.0 km · Catacaos 9.0 km · La Unión 25 km · Sullana 31 km · Marcavelica 34 km · Querecotillo 39 km · Sechura 45 km · Tambo Grande 46 km

Peru travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type A / B / C
220 V · 60 Hz
Prices
≈ 51% of US
price level, 2025
GDP per capita
$9,684
2025
Happiness
6.0 / 10
World Happiness, 2025
Safe drinking water
49%
of population, 2024
Homicide rate
8.6
per 100k, 2021
Road deaths
13.6
per 100k/yr, 2019
Income group
Upper middle
World Bank
English
Moderate
EF EPI 519
Religion
Catholic 76%Evangelical Christian 16%no religion 5%other religions 3%

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 San Martin (-5.1859°, -80.6693°, elevation 35 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).