La Unión weather in September

In September, La Unión sees average daytime highs of 26°C and overnight lows near 17°C, with 1 mm of rain across 0.3 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 26°C through the month. The sky is clear or mostly clear about 51% 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 La Unión's 4th-clearest and 1st-windiest month. For the whole year in context, see La Unión's year-round climate.

Daytime high
26°
10th warmest
Overnight low
17°
2nd coldest
Rainfall
1 mm
0.3 wet days
Daylight
12 hours
6:18 AM – 6:16 PM
Cloud cover
44%
4th clearest
Wind
15 km/h
1st windiest
Solar energy
6.45 kWh/m²
Travel score
8.5
out of 10

La Unión is city in Piura, Peru.

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

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 26°C through the month.

A typical September day in La Unión reaches about 26°C in the afternoon and slips back to 17°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 24°C and 27°C. Set against its neighbours, September runs about 1°C warmer than August and about 1°C cooler than October.

15°20°25°30°151015202530
Avg high (°C)Avg low (°C)
12517
22517
32517
42517
52517
62517
72517
82517
92517
102517
112517
122517
132517
142617
152617
162617
172617
182617
192617
202617
212617
222617
232617
242617
252617
262617
272617
282617
292617
302617

How September really feels in La Unión

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.

La Unión 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
Jan30° / 22°232.712.35.5
Feb31° / 23°375.612.24.7
Mar31° / 23°586.9124.5
Apr30° / 22°213.611.95.6
May29° / 20°31.111.87.1
Jun26° / 19°10.311.78.4
Jul25° / 18°00.111.78.8
Aug25° / 17°00.111.89.0
Sep26° / 17°10.3128.5
Oct26° / 18°20.812.18.1
Nov27° / 18°41.212.27.7
Dec29° / 20°102.612.36.6

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 51% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 20% 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
27822
37723
47624
57624
67525
77525
87426
97426
107426
117327
127327
137327
147228
157228
167129
177129
187129
197030
207030
217030
226931
236832
246832
256733
266733
276634
286535
296535
306535

Chance of precipitation in September

Any precipitation

La Unión gets around 1 mm of rain over 0.3 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 1% and peaks near 2% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
10
20
30
40
50
60
70
80
90
100
110
120
130
140
151
161
171
181
191
201
211
222
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 61% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Comfortable (%)Humid (%)Muggy (%)
161363
260373
360373
460373
560373
660373
760373
860373
960373
1060373
1160373
1260373
1360373
1460373
1561363
1661363
1761363
1861363
1961363
2062353
2162353
2262353
2362353
2462353
2563343
2663343
2763343
2862353
2962353
3062353

Wind in September

Winds average 15 km/h in September, the windiest month of the year.

Across September, daily wind ranges from about 15 km/h on the calmest days to 15 km/h at its breeziest. It stays fairly steady from day to day.

05101520151015202530
Wind speed (km/h)Feels
115light breeze
215light breeze
315light breeze
415light breeze
515light breeze
615light breeze
715light breeze
815light breeze
915light breeze
1015light breeze
1115light breeze
1215light breeze
1315light breeze
1415light breeze
1515light breeze
1615light breeze
1715light breeze
1815light breeze
1915light breeze
2015light breeze
2115light breeze
2215light breeze
2315light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light 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 6:26 AM to 6:11 AM, and sunset from 6:20 PM to 6:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
111.96:266:20
211.96:256:19
311.96:256:19
411.96:246:19
511.96:246:19
611.96:236:19
711.96:236:18
811.96:226:18
911.96:226:18
1011.96:216:18
1111.96:216:18
1212.06:206:17
1312.06:206:17
1412.06:196:17
1512.06:196:17
1612.06:186:16
1712.06:186:16
1812.06:176:16
1912.06:176:16
2012.06:166:16
2112.06:166:15
2212.06:156:15
2312.06:156:15
2412.06:146:15
2512.06:136:14
2612.06:136:14
2712.06:126:14
2812.06:126:14
2912.06:126:14
3012.06:116:14

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.45 kWh/m².

For context, solar energy here swings from a low near 5.3 kWh/m² to a high of 6.62 kWh/m² in October across the year — September's 6.45 kWh/m² sits near the top of that range.

0246151015202530
Solar energy (kWh/m²)Level
16.3Intense
26.3Intense
36.3Intense
46.3Intense
56.3Intense
66.3Intense
76.3Intense
86.3Intense
96.4Intense
106.4Intense
116.4Intense
126.4Intense
136.4Intense
146.5Intense
156.5Intense
166.5Intense
176.5Intense
186.5Intense
196.5Intense
206.5Intense
216.5Intense
226.5Intense
236.5Intense
246.5Intense
256.5Intense
266.6Intense
276.6Intense
286.6Intense
296.6Intense
306.6Intense
Planning a trip in September

Is September a good time to visit La Unión?

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

8.5
Sightseeing
3rd-best month of the year
7.9
Beach & pool
5th-best month of the year

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

What to pack for La Unión in September

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

In September, La Unión sees daytime highs around 26°C and nights near 17°C. Pack sun protection. Worth having: light clothes.

sun protectionlight clothes

Sea temperature near La Unión 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 29 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 La Unión 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 La Unión 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 (very high).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecExtremeExtremeFeb 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 La Unión?

La Unión sits at 5.4°S, 80.7°W, 15 m above sea level, in Peru. The nearest listed city is Catacaos, 16 km away.

Topography around La Unión

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

Within 3 km, the terrain around La Unión has only modest variations in elevation — a maximum elevation change of 25 m around an average of 14 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 76 m; within 80 km, significant variations in elevation — a maximum elevation change of 588 m.

The land around La Unión is covered by cropland (57%) within 3 km, bare terrain (50%) and cropland (33%) within 16 km, and bare terrain (47%) and water (24%) within 80 km.

3 km
25 m
16 km
76 m
80 km
588 m
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Catacaos 16 km · Sechura 19 km · San Martin 25 km · Piura 26 km · Paita 54 km · Sullana 56 km · Marcavelica 58 km · Querecotillo 64 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 La Unión (-5.4023°, -80.7422°, elevation 15 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).