Aarau weather in May

In May, Aarau sees average daytime highs of 18°C and overnight lows near 9°C, with 148 mm of precipitation across 17.3 wet days and about 14.9 hours of daylight. It is the 5th-warmest and 2nd-wettest month of the year here.

Highs climb over the month, from about 16°C in the first days to 19°C by the end. The sky is clear or mostly clear about 19% of the time in May, and the air most often feels dry.

Daylight stretches from about 14 h 12 min at the start of May to 15 h 24 min by month's end. Set against the rest of the year, May is Aarau's 8th-clearest and 6th-windiest month. For the whole year in context, see Aarau's year-round climate.

Daytime high: 18°; 5th warmest
Overnight low: 9°; 8th coldest
Precipitation: 148 mm; 17.3 wet days
Daylight: 14 h 54 min; 4:58 AM – 7:51 PM
Cloud cover: 67%; 8th clearest
Wind: 7 km/h; 6th windiest
Solar energy: 5.15 kWh/m²
Travel score: 4.7; out of 10

Aarau is capital of Canton Aargau, Switzerland.

Air quality: Good; PM2.5 8.9 µg/m³ · 2020
Density: 1,743/km²; people per km²
Founded: 1240

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

← April Aarau year-round climate June →Best places to visit in May

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 16°C in the first days to 19°C by the end.

A typical May day in Aarau reaches about 18°C in the afternoon and slips back to 9°C overnight — a 9°C spread between the day's warmth and the night's chill. On most days the high lands between 11°C and 24°C. Set against its neighbours, May runs about 4°C warmer than April and about 4°C cooler than June.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Avg high (°C)	16	16	16	16	16	17	17	17	17	17	17	17	17	17	18	18	18	18	18	18	18	19	19	19	19	19	19	19	19	20	20
Avg low (°C)	7	7	7	8	8	8	8	8	8	8	8	8	8	8	9	9	9	9	9	9	9	9	9	10	10	10	10	10	10	10	11

	Avg high (°C)	Avg low (°C)
1	16	7
2	16	7
3	16	7
4	16	8
5	16	8
6	17	8
7	17	8
8	17	8
9	17	8
10	17	8
11	17	8
12	17	8
13	17	8
14	17	8
15	18	9
16	18	9
17	18	9
18	18	9
19	18	9
20	18	9
21	18	9
22	19	9
23	19	9
24	19	10
25	19	10
26	19	10
27	19	10
28	19	10
29	19	10
30	20	10
31	20	11

How May really feels in Aarau

Once humidity and wind are folded in, May 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

heat index over the day's high

Days feeling ≤ 0°C

wind chill below the day's low

May sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Aarau weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 2nd-wettest month here — the current month is highlighted below.

Month	High / Low (°C)	Rainfall (mm)	Wet days	Snow days	Daylight (hours)	Travel score
Jan	3° / -2°	97	13.4	7	8.7	0.0
Feb	5° / -1°	80	10.9	6.4	9.9	0.2
Mar	10° / 2°	97	14.2	4.4	11.6	1.9
Apr	14° / 5°	100	14.5	2.1	13.3	3.5
May	18° / 9°	148	17.3	0	14.9	4.7
Jun	21° / 12°	142	17.4	0	15.7	5.4
Jul	23° / 14°	152	17	0	15.3	5.9
Aug	23° / 13°	145	16.5	0	14.1	5.9
Sep	18° / 10°	108	13.2	0	12.4	5.3
Oct	13° / 6°	103	13.2	0.3	10.6	3.4
Nov	7° / 2°	100	13.1	3.3	9.1	0.9
Dec	4° / -1°	116	14.3	6.7	8.3	0.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 19% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 15% of May, with mostly cloudy or overcast conditions the remaining 67%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Clearer (%)	30	29	29	29	29	30	30	30	30	31	31	31	31	32	32	33	34	34	35	35	35	36	36	36	37	37	37	37	38	37	36
Cloudier (%)	70	71	71	71	71	70	70	70	70	69	69	69	69	68	68	67	66	66	65	65	65	64	64	64	63	63	63	63	62	63	64

	Clearer (%)	Cloudier (%)
1	30	70
2	29	71
3	29	71
4	29	71
5	29	71
6	30	70
7	30	70
8	30	70
9	30	70
10	31	69
11	31	69
12	31	69
13	31	69
14	32	68
15	32	68
16	33	67
17	34	66
18	34	66
19	35	65
20	35	65
21	35	65
22	36	64
23	36	64
24	36	64
25	37	63
26	37	63
27	37	63
28	37	63
29	38	62
30	37	63
31	36	64

Chance of precipitation in May

Any precipitationSnow

Aarau gets around 148 mm of rain and snow over 17.3 wet days in May. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 56% and peaks near 59% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Rain chance (%)	57	58	58	59	59	59	59	59	59	59	58	58	58	57	57	57	56	55	55	54	54	53	53	53	53	53	53	54	54	55	56
Snow chance (%)	2	1	1	1	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

	Rain chance (%)	Snow chance (%)
1	57	2
2	58	1
3	58	1
4	59	1
5	59	1
6	59	1
7	59	0
8	59	0
9	59	0
10	59	0
11	58	0
12	58	0
13	58	0
14	57	0
15	57	0
16	57	0
17	56	0
18	55	0
19	55	0
20	54	0
21	54	0
22	53	0
23	53	0
24	53	0
25	53	0
26	53	0
27	53	0
28	54	0
29	54	0
30	55	0
31	56	0

Humidity in May

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, May lands in the dry band about 93% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Dry (%)	99	99	99	99	99	99	98	98	98	98	98	98	97	97	96	96	95	95	94	93	92	91	90	88	87	86	84	82	81	79	78
Comfortable (%)	1	1	1	1	1	1	2	2	2	2	2	2	3	3	4	4	5	5	6	7	8	9	10	12	13	14	15	17	18	19	20
Humid (%)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1	1	1	2	2

	Dry (%)	Comfortable (%)	Humid (%)
1	99	1	0
2	99	1	0
3	99	1	0
4	99	1	0
5	99	1	0
6	99	1	0
7	98	2	0
8	98	2	0
9	98	2	0
10	98	2	0
11	98	2	0
12	98	2	0
13	97	3	0
14	97	3	0
15	96	4	0
16	96	4	0
17	95	5	0
18	95	5	0
19	94	6	0
20	93	7	0
21	92	8	0
22	91	9	0
23	90	10	0
24	88	12	0
25	87	13	0
26	86	14	0
27	84	15	1
28	82	17	1
29	81	18	1
30	79	19	2
31	78	20	2

Wind in May

Winds average 7 km/h in May.

Across May, daily wind ranges from about 7 km/h on the calmest days to 7 km/h at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Wind speed (km/h)	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7	7
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (km/h)	Feels
1	7	calm
2	7	calm
3	7	calm
4	7	calm
5	7	calm
6	7	calm
7	7	calm
8	7	calm
9	7	calm
10	7	calm
11	7	calm
12	7	calm
13	7	calm
14	7	calm
15	7	calm
16	7	calm
17	7	calm
18	7	calm
19	7	calm
20	7	calm
21	7	calm
22	7	calm
23	7	calm
24	7	calm
25	7	calm
26	7	calm
27	7	calm
28	7	calm
29	7	calm
30	7	calm
31	7	calm

Sunrise & sunset in May

DaylightNight

Daylight runs from about 14 h 12 min at the start of May to 15 h 24 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 72 minutes over May. Sunrise moves from 5:20 AM to 4:43 AM, and sunset from 7:30 PM to 8:08 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Daylight (h)	14.2	14.2	14.3	14.3	14.4	14.4	14.5	14.5	14.6	14.6	14.7	14.7	14.8	14.8	14.8	14.9	14.9	15.0	15.0	15.0	15.1	15.1	15.2	15.2	15.2	15.3	15.3	15.3	15.4	15.4	15.4
Sunrise (AM)	5:20	5:18	5:16	5:15	5:13	5:12	5:10	5:09	5:07	5:06	5:04	5:03	5:01	5:00	4:59	4:58	4:56	4:55	4:54	4:53	4:52	4:51	4:50	4:49	4:48	4:47	4:46	4:45	4:44	4:43	4:43
Sunset (PM)	7:30	7:32	7:33	7:35	7:36	7:37	7:39	7:40	7:41	7:43	7:44	7:45	7:47	7:48	7:49	7:51	7:52	7:53	7:54	7:56	7:57	7:58	7:59	8:00	8:01	8:03	8:04	8:05	8:06	8:07	8:08

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	14.2	5:20	7:30
2	14.2	5:18	7:32
3	14.3	5:16	7:33
4	14.3	5:15	7:35
5	14.4	5:13	7:36
6	14.4	5:12	7:37
7	14.5	5:10	7:39
8	14.5	5:09	7:40
9	14.6	5:07	7:41
10	14.6	5:06	7:43
11	14.7	5:04	7:44
12	14.7	5:03	7:45
13	14.8	5:01	7:47
14	14.8	5:00	7:48
15	14.8	4:59	7:49
16	14.9	4:58	7:51
17	14.9	4:56	7:52
18	15.0	4:55	7:53
19	15.0	4:54	7:54
20	15.0	4:53	7:56
21	15.1	4:52	7:57
22	15.1	4:51	7:58
23	15.2	4:50	7:59
24	15.2	4:49	8:00
25	15.2	4:48	8:01
26	15.3	4:47	8:03
27	15.3	4:46	8:04
28	15.3	4:45	8:05
29	15.4	4:44	8:06
30	15.4	4:43	8:07
31	15.4	4:43	8:08

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.15 kWh/m².

For context, solar energy here swings from a low near 1 kWh/m² to a high of 5.61 kWh/m² in June across the year — May's 5.15 kWh/m² sits near the top of that range.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31
Solar energy (kWh/m²)	4.8	4.8	4.8	4.8	4.8	4.8	4.9	4.9	4.9	4.9	5.0	5.0	5.0	5.1	5.1	5.1	5.2	5.2	5.2	5.3	5.3	5.3	5.4	5.4	5.4	5.4	5.4	5.4	5.5	5.5	5.4
Level	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	4.8	Bright
2	4.8	Bright
3	4.8	Bright
4	4.8	Bright
5	4.8	Bright
6	4.8	Bright
7	4.9	Bright
8	4.9	Bright
9	4.9	Bright
10	4.9	Bright
11	5.0	Bright
12	5.0	Bright
13	5.0	Bright
14	5.1	Bright
15	5.1	Bright
16	5.1	Bright
17	5.2	Bright
18	5.2	Bright
19	5.2	Bright
20	5.3	Bright
21	5.3	Bright
22	5.3	Bright
23	5.4	Bright
24	5.4	Bright
25	5.4	Bright
26	5.4	Bright
27	5.4	Bright
28	5.4	Bright
29	5.5	Bright
30	5.5	Bright
31	5.4	Bright

Planning a trip in May

Is May a good time to visit Aarau?

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

4.7

Sightseeing

5th-best month of the year

1.5

Beach & pool

5th-best month of the year

May is a reasonable time to visit Aarau for sightseeing.

What to pack for Aarau in May

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

In May, Aarau sees daytime highs around 18°C and nights near 9°C. Pack rain gear. Worth having: sun protection. About 17 days see rain.

rain gearsun protection

UV index in Aarau in May

LowModerateHighVery highExtreme

Clear-sky midday UV in May peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Aarau peaks around July 15 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
UV index (midday)	1	2	4	5	7	7	8	7	4	3	2	1
Level	Low	Moderate	Moderate	Moderate	High	Very high	Very high	High	Moderate	Moderate	Low	Low

	UV index (midday)	Level
Jan	1	Low
Feb	2	Moderate
Mar	4	Moderate
Apr	5	Moderate
May	7	High
Jun	7	Very high
Jul	8	Very high
Aug	7	High
Sep	4	Moderate
Oct	3	Moderate
Nov	2	Low
Dec	1	Low

Location & terrain

Where is Aarau?

Aarau sits at 47.4°N, 8.0°E, 389 m above sea level, in Switzerland. The nearest listed city is Olten, 12 km away.

Topography around Aarau

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

Within 3 km, the terrain around Aarau has only modest variations in elevation — a maximum elevation change of 198 m around an average of 416 m above sea level; within 16 km, large variations in elevation — a maximum elevation change of 695 m; within 80 km, extreme variations in elevation — a maximum elevation change of 2,987 m.

The land around Aarau is covered by trees (48%) and artificial surfaces (26%) within 3 km, trees (50%) and grassland (24%) within 16 km, and trees (47%) and grassland (28%) within 80 km.

3 km

198 m

trees 48%

16 km

695 m

trees 50%

80 km

2,987 m

trees 47%

treesgrasslandcroplandartificial surfacesbare terrainwater

← April Aarau year-round climate June →Best places to visit in May

May weather nearby: Olten 12 km · Bad Säckingen 19 km · Baden 22 km · Wettingen 23 km · Dietikon 27 km · Rheinfelden 27 km · Waldshut-Tiengen 29 km · Zürich (Kreis 9) 33 km

Switzerland travel facts

Travel advisory: Level 1; Exercise Normal Precautions
Power plugs: Type C / J; 230 V · 50 Hz
Prices: ≈ 112% of US; price level, 2025
GDP per capita: $114,769; 2025
Happiness: 7.0 / 10; World Happiness, 2025
Safe drinking water: 97%; of population, 2024
Homicide rate: 0.6; per 100k, 2023
Road deaths: 2.2; per 100k/yr, 2019
Income group: High; World Bank
English: High; EF EPI 564
Religion

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 Aarau (47.3925°, 8.0442°, elevation 389 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. 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).

	Avg high (°C)	Avg low (°C)
1	16	7
2	16	7
3	16	7
4	16	8
5	16	8
6	17	8
7	17	8
8	17	8
9	17	8
10	17	8
11	17	8
12	17	8
13	17	8
14	17	8
15	18	9
16	18	9
17	18	9
18	18	9
19	18	9
20	18	9
21	18	9
22	19	9
23	19	9
24	19	10
25	19	10
26	19	10
27	19	10
28	19	10
29	19	10
30	20	10
31	20	11

	Clearer (%)	Cloudier (%)
1	30	70
2	29	71
3	29	71
4	29	71
5	29	71
6	30	70
7	30	70
8	30	70
9	30	70
10	31	69
11	31	69
12	31	69
13	31	69
14	32	68
15	32	68
16	33	67
17	34	66
18	34	66
19	35	65
20	35	65
21	35	65
22	36	64
23	36	64
24	36	64
25	37	63
26	37	63
27	37	63
28	37	63
29	38	62
30	37	63
31	36	64

	Rain chance (%)	Snow chance (%)
1	57	2
2	58	1
3	58	1
4	59	1
5	59	1
6	59	1
7	59	0
8	59	0
9	59	0
10	59	0
11	58	0
12	58	0
13	58	0
14	57	0
15	57	0
16	57	0
17	56	0
18	55	0
19	55	0
20	54	0
21	54	0
22	53	0
23	53	0
24	53	0
25	53	0
26	53	0
27	53	0
28	54	0
29	54	0
30	55	0
31	56	0

	Dry (%)	Comfortable (%)	Humid (%)
1	99	1	0
2	99	1	0
3	99	1	0
4	99	1	0
5	99	1	0
6	99	1	0
7	98	2	0
8	98	2	0
9	98	2	0
10	98	2	0
11	98	2	0
12	98	2	0
13	97	3	0
14	97	3	0
15	96	4	0
16	96	4	0
17	95	5	0
18	95	5	0
19	94	6	0
20	93	7	0
21	92	8	0
22	91	9	0
23	90	10	0
24	88	12	0
25	87	13	0
26	86	14	0
27	84	15	1
28	82	17	1
29	81	18	1
30	79	19	2
31	78	20	2

	Avg high (°C)	Avg low (°C)
1	16	7
2	16	7
3	16	7
4	16	8
5	16	8
6	17	8
7	17	8
8	17	8
9	17	8
10	17	8
11	17	8
12	17	8
13	17	8
14	17	8
15	18	9
16	18	9
17	18	9
18	18	9
19	18	9
20	18	9
21	18	9
22	19	9
23	19	9
24	19	10
25	19	10
26	19	10
27	19	10
28	19	10
29	19	10
30	20	10
31	20	11

	Clearer (%)	Cloudier (%)
1	30	70
2	29	71
3	29	71
4	29	71
5	29	71
6	30	70
7	30	70
8	30	70
9	30	70
10	31	69
11	31	69
12	31	69
13	31	69
14	32	68
15	32	68
16	33	67
17	34	66
18	34	66
19	35	65
20	35	65
21	35	65
22	36	64
23	36	64
24	36	64
25	37	63
26	37	63
27	37	63
28	37	63
29	38	62
30	37	63
31	36	64

	Rain chance (%)	Snow chance (%)
1	57	2
2	58	1
3	58	1
4	59	1
5	59	1
6	59	1
7	59	0
8	59	0
9	59	0
10	59	0
11	58	0
12	58	0
13	58	0
14	57	0
15	57	0
16	57	0
17	56	0
18	55	0
19	55	0
20	54	0
21	54	0
22	53	0
23	53	0
24	53	0
25	53	0
26	53	0
27	53	0
28	54	0
29	54	0
30	55	0
31	56	0

	Dry (%)	Comfortable (%)	Humid (%)
1	99	1	0
2	99	1	0
3	99	1	0
4	99	1	0
5	99	1	0
6	99	1	0
7	98	2	0
8	98	2	0
9	98	2	0
10	98	2	0
11	98	2	0
12	98	2	0
13	97	3	0
14	97	3	0
15	96	4	0
16	96	4	0
17	95	5	0
18	95	5	0
19	94	6	0
20	93	7	0
21	92	8	0
22	91	9	0
23	90	10	0
24	88	12	0
25	87	13	0
26	86	14	0
27	84	15	1
28	82	17	1
29	81	18	1
30	79	19	2
31	78	20	2

	Avg high (°C)	Avg low (°C)
1	16	7
2	16	7
3	16	7
4	16	8
5	16	8
6	17	8
7	17	8
8	17	8
9	17	8
10	17	8
11	17	8
12	17	8
13	17	8
14	17	8
15	18	9
16	18	9
17	18	9
18	18	9
19	18	9
20	18	9
21	18	9
22	19	9
23	19	9
24	19	10
25	19	10
26	19	10
27	19	10
28	19	10
29	19	10
30	20	10
31	20	11

	Clearer (%)	Cloudier (%)
1	30	70
2	29	71
3	29	71
4	29	71
5	29	71
6	30	70
7	30	70
8	30	70
9	30	70
10	31	69
11	31	69
12	31	69
13	31	69
14	32	68
15	32	68
16	33	67
17	34	66
18	34	66
19	35	65
20	35	65
21	35	65
22	36	64
23	36	64
24	36	64
25	37	63
26	37	63
27	37	63
28	37	63
29	38	62
30	37	63
31	36	64

	Rain chance (%)	Snow chance (%)
1	57	2
2	58	1
3	58	1
4	59	1
5	59	1
6	59	1
7	59	0
8	59	0
9	59	0
10	59	0
11	58	0
12	58	0
13	58	0
14	57	0
15	57	0
16	57	0
17	56	0
18	55	0
19	55	0
20	54	0
21	54	0
22	53	0
23	53	0
24	53	0
25	53	0
26	53	0
27	53	0
28	54	0
29	54	0
30	55	0
31	56	0

	Dry (%)	Comfortable (%)	Humid (%)
1	99	1	0
2	99	1	0
3	99	1	0
4	99	1	0
5	99	1	0
6	99	1	0
7	98	2	0
8	98	2	0
9	98	2	0
10	98	2	0
11	98	2	0
12	98	2	0
13	97	3	0
14	97	3	0
15	96	4	0
16	96	4	0
17	95	5	0
18	95	5	0
19	94	6	0
20	93	7	0
21	92	8	0
22	91	9	0
23	90	10	0
24	88	12	0
25	87	13	0
26	86	14	0
27	84	15	1
28	82	17	1
29	81	18	1
30	79	19	2
31	78	20	2