Johnstone weather in September

In September, Johnstone sees average daytime highs of 16°C and overnight lows near 10°C, with 90 mm of rain across 14.1 wet days and about 12.5 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 17°C in the first days to 14°C by the end. The sky is clear or mostly clear about 8% of the time in September, and the air most often feels dry.

Daylight stretches from about 13 h 36 min at the start of September to 11 h 18 min by month's end. Set against the rest of the year, September is Johnstone's 8th-clearest and 8th-windiest month. For the whole year in context, see Johnstone's year-round climate.

Daytime high
16°
4th warmest
Overnight low
10°
9th coldest
Rainfall
90 mm
14.1 wet days
Daylight
12 h 30 min
5:59 AM – 6:26 PM
Cloud cover
77%
8th clearest
Wind
14 km/h
8th windiest
Solar energy
2.46 kWh/m²
Travel score
4.2
out of 10

Johnstone is town in Renfrewshire, Scotland, UK.

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 17°C in the first days to 14°C by the end.

A typical September day in Johnstone reaches about 16°C in the afternoon and slips back to 10°C overnight — a 6°C spread between the day's warmth and the night's chill. On most days the high lands between 13°C and 18°C. Set against its neighbours, September runs about 2°C cooler than August and about 3°C warmer than October.

10°15°20°151015202530
Avg high (°C)Avg low (°C)
11711
21711
31711
41711
51710
61610
71610
81610
91610
101610
111610
121610
131610
141610
151610
161610
171610
181510
19159
20159
21159
22159
23159
24159
25159
26159
27159
28149
29149
30149

How September really feels in Johnstone

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.

Johnstone weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 12617.52.57.40.6
Feb / 10214.72.49.20.8
Mar / 9214.91.711.41.5
Apr11° / 7714.10.513.82.5
May14° / 7813.60.2163.7
Jun16° / 10°8414.4017.24.4
Jul18° / 12°9215.7016.74.8
Aug18° / 11°10516.4014.84.8
Sep16° / 10°9014.1012.54.2
Oct12° / 12316.1010.12.8
Nov / 11816.90.381.5
Dec / 12416.31.86.80.8

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 8% of the time in September.

Beyond those clear spells, partly cloudy skies cover about 14% of September, with mostly cloudy or overcast conditions the remaining 78%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
12278
22278
32179
42179
52179
62179
72080
82080
92080
102179
112278
122278
132278
142278
152278
162377
172476
182476
192476
202377
212377
222377
232377
242377
252377
262377
272377
282179
292179
302179

Chance of precipitation in September

Any precipitation

Johnstone gets around 90 mm of rain over 14.1 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 47% and peaks near 51% on the wettest days.

0%20%40%60%151015202530
Rain chance (%)
146
246
346
446
547
647
747
848
948
1048
1148
1247
1347
1447
1546
1646
1745
1845
1945
2045
2145
2246
2346
2447
2548
2649
2750
2851
2951
3051

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 88% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
182171
282171
383161
483161
583161
684151
784151
884151
985141
1086131
1187130
1288120
1389110
1489110
1589110
1689110
1790100
1890100
1990100
2090100
2190100
2290100
2390100
249190
259190
269190
279190
289280
299280
309370

Wind in September

Winds average 14 km/h in September.

Across September, daily wind ranges from about 14 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
114light breeze
214light breeze
314light breeze
414light breeze
514light breeze
614light breeze
714light breeze
814light breeze
914light breeze
1014light breeze
1114light breeze
1214light breeze
1314light breeze
1414light breeze
1514light breeze
1614light breeze
1714light breeze
1814light breeze
1914light breeze
2014light breeze
2114light breeze
2214light breeze
2314light breeze
2415light breeze
2515light breeze
2615light breeze
2715light breeze
2815light breeze
2915light breeze
3015light breeze

Sunrise & sunset in September

DaylightNight

Daylight runs from about 13 h 36 min at the start of September to 11 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 138 minutes over September. Sunrise moves from 5:29 AM to 6:27 AM, and sunset from 7:07 PM to 5:48 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
113.65:297:07
213.65:317:04
313.55:337:01
413.45:356:59
513.35:376:56
613.25:396:53
713.25:416:51
813.15:436:48
913.05:456:45
1012.95:476:42
1112.95:496:40
1212.85:516:37
1312.75:536:34
1412.65:556:32
1512.55:576:29
1612.55:596:26
1712.46:016:23
1812.36:036:21
1912.26:056:18
2012.16:076:15
2112.16:096:12
2212.06:116:10
2311.96:136:07
2411.86:156:04
2511.76:176:01
2611.76:195:59
2711.66:215:56
2811.56:235:53
2911.46:255:50
3011.36:275:48

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 2.46 kWh/m².

For context, solar energy here swings from a low near 0.37 kWh/m² to a high of 4.76 kWh/m² in May across the year — September's 2.46 kWh/m² falls in the middle.

01234151015202530
Solar energy (kWh/m²)Level
13.0Moderate
23.0Moderate
33.0Moderate
42.9Moderate
52.9Moderate
62.8Moderate
72.8Moderate
82.8Moderate
92.7Moderate
102.7Moderate
112.6Moderate
122.6Moderate
132.6Moderate
142.5Moderate
152.5Moderate
162.5Moderate
172.4Moderate
182.4Moderate
192.4Moderate
202.3Moderate
212.3Moderate
222.2Moderate
232.2Moderate
242.1Moderate
252.1Moderate
262.1Moderate
272.0Moderate
282.0Dim
291.9Dim
301.9Dim
Planning a trip in September

Is September a good time to visit Johnstone?

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

4.2
Sightseeing
4th-best month of the year
0.4
Beach & pool
4th-best month of the year

September is a reasonable time to visit Johnstone for sightseeing.

What to pack for Johnstone in September

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

In September, Johnstone sees daytime highs around 16°C and nights near 10°C. Pack rain gear. Worth having: a warm layer. About 14 days see rain.

rain geara warm layer

Sea temperature near Johnstone in September

The nearest coast averages about 14°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 24 km away) is warmest in August at about 15°C and coldest in February near 7°C.

The water stays below 20°C all year — cool enough that most swimmers want a wetsuit.

5°10°15°JanFebMarAprMayJunJulAugSepOctNovDecbracingcool
Sea temperature (°C)Comfort
Jan8Bracing
Feb7Bracing
Mar7Bracing
Apr8Bracing
May10Bracing
Jun13Bracing
Jul15Bracing
Aug15Cool
Sep14Bracing
Oct12Bracing
Nov11Bracing
Dec9Bracing

UV index in Johnstone in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 3 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Johnstone peaks around June 18 at about 5 (high) — a little sun protection helps at midday. It bottoms out near December 20 at about 0 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 5 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowJun 18UV 5Dec 20UV 0
UV index (midday)Level
Jan0Low
Feb1Low
Mar2Moderate
Apr3Moderate
May5Moderate
Jun5High
Jul5Moderate
Aug5Moderate
Sep3Moderate
Oct2Low
Nov1Low
Dec0Low
Location & terrain

Where is Johnstone?

Johnstone sits at 55.8°N, 4.5°W, 36 m above sea level, in United Kingdom. The nearest listed city is Paisley, 5.0 km away.

Topography around Johnstone

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

Within 3 km, the terrain around Johnstone has only modest variations in elevation — a maximum elevation change of 214 m around an average of 63 m above sea level; within 16 km, significant variations in elevation — a maximum elevation change of 517 m; within 80 km, large variations in elevation — a maximum elevation change of 1,163 m.

The land around Johnstone is covered by grassland (48%), trees (27%) and artificial surfaces (20%) within 3 km, grassland (61%) within 16 km, and grassland (55%) and trees (20%) within 80 km.

3 km
214 m
16 km
517 m
80 km
1,163 m
treesgrasslandcroplandartificial surfaceswater
September weather nearby: Paisley 5.0 km · Barrhead 8.0 km · Erskine 9.0 km · Renfrew 9.0 km · Clydebank 11 km · Newton Mearns 13 km · Dumbarton 13 km · Bearsden 15 km

United Kingdom travel facts

Travel advisory
Level 2
Exercise Increased Caution
Power plugs
Type D / G / M
230 V · 50 Hz
Prices
≈ 89% of US
price level, 2025
GDP per capita
$57,602
2025
Happiness
6.7 / 10
World Happiness, 2025
Safe drinking water
100%
of population, 2024
Homicide rate
1.1
per 100k, 2021
Road deaths
3.2
per 100k/yr, 2019
Income group
High
World Bank
Religion
Christian 60%none 26%Muslim 4%other 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 Johnstone (55.8291°, -4.516°, elevation 36 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).