Marshalltown weather in May

In May, Marshalltown sees average daytime highs of 70°F and overnight lows near 51°F, with 5.3 in of precipitation across 13.5 wet days and about 14.3 hours of daylight. It is the 5th-warmest and 1st-wettest month of the year here.

Highs climb over the month, from about 66°F in the first days to 75°F by the end. The sky is clear or mostly clear about 26% of the time in May, and the air most often feels dry.

Daylight stretches from about 13 h 48 min at the start of May to 14 h 48 min by month's end. Set against the rest of the year, May is Marshalltown's 9th-clearest and 7th-windiest month. For the whole year in context, see Marshalltown's year-round climate.

Daytime high
70°
5th warmest
Overnight low
51°
8th coldest
Precipitation
5.3 in
13.5 wet days
Daylight
14 h 24 min
4:57 AM – 7:19 PM
Cloud cover
63%
9th clearest
Wind
10 mph
7th windiest
Solar energy
5.65 kWh/m²
Travel score
6.0
out of 10

Marshalltown is city and the county seat of Marshall County, Iowa, United States.

Density
552/km²
people per km²
Founded
1853

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

Temperature in May

Average highAverage lowShaded bands: 10–90% of days

Highs climb over the month, from about 66°F in the first days to 75°F by the end.

A typical May day in Marshalltown reaches about 70°F in the afternoon and slips back to 51°F overnight — a 19°F spread between the day's warmth and the night's chill. On most days the high lands between 58°F and 82°F. Set against its neighbours, May runs about 11°F warmer than April and about 9°F cooler than June.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
16546
26546
36647
46647
56747
66748
76748
86849
96849
106949
116950
126950
137050
147051
157051
167151
177152
187152
197153
207253
217253
227254
237354
247354
257355
267455
277455
287456
297556
307556
317557

How May really feels in Marshalltown

Once humidity and wind are folded in, May averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F
0
heat index over the day's high
Days feeling ≤ 32°F
0
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.

Marshalltown weather by month

How May compares with the rest of the year at a glance. May is the 5th-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan28° / 13°1.36.54.99.30.0
Feb33° / 16°1.56.44.710.30.0
Mar46° / 28°2.58.62.911.71.5
Apr60° / 40°4.511.5113.14.5
May70° / 51°5.313.50.114.36.0
Jun79° / 62°5.211.80156.3
Jul82° / 65°3.810.1014.76.3
Aug80° / 62°3.99.1013.76.8
Sep74° / 54°3.78.4012.37.2
Oct61° / 42°2.97.90.410.95.4
Nov46° / 29°2.16.71.69.61.5
Dec33° / 19°1.66.34.790.0

Cloud cover in May

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 26% of the time in May.

Beyond those clear spells, partly cloudy skies cover about 17% of May, with mostly cloudy or overcast conditions the remaining 57%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13961
23961
33961
43961
53961
63961
73961
83961
94060
104159
114159
124159
134159
144159
154159
164258
174258
184357
194357
204456
214456
224456
234555
244654
254555
264654
274654
284753
294753
304753
314852

Chance of precipitation in May

Any precipitation

Marshalltown gets around 5.3 in of rain and snow over 13.5 wet days in May, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 43% and peaks near 47% on the wettest days, and about 0 day brings snow.

0%20%40%60%151015202531
Rain chance (%)
143
243
343
443
544
644
744
843
943
1043
1142
1242
1341
1441
1541
1641
1741
1841
1942
2042
2143
2243
2344
2444
2545
2645
2746
2846
2947
3047
3147

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 71% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
188930
287940
3861040
4841150
5821161
6811261
7801271
8781381
9781381
10761491
11761491
127514101
137514101
147414102
157414102
167314112
177214113
187114123
196915124
206815134
216715135
226615145
236316156
246216157
256116167
265917168
275817178
285618179
2954181810
3053191810
3151191911

Wind in May

Winds average 10 mph in May.

Across May, daily wind ranges from about 9 mph on the calmest days to 10 mph at its breeziest. It stays fairly steady from day to day.

051015151015202531
Wind speed (mph)Feels
110light breeze
210light breeze
310light breeze
410light breeze
510light breeze
610light breeze
710light breeze
810light breeze
910light breeze
1010light breeze
1110light breeze
1210light breeze
1310light breeze
1410light breeze
1510light breeze
1610light breeze
1710light breeze
1810light breeze
1910light breeze
2010light breeze
219light breeze
229light breeze
239light breeze
249light breeze
259light breeze
269light breeze
279light breeze
289light breeze
299light breeze
309light breeze
319light breeze

Sunrise & sunset in May

DaylightNight

Daylight runs from about 13 h 48 min at the start of May to 14 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days grow by about 60 minutes over May. Sunrise moves from 5:15 AM to 4:45 AM, and sunset from 7:03 PM to 7:33 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.85:157:03
213.85:137:04
313.95:127:05
413.95:117:06
514.05:097:07
614.05:087:08
714.05:077:09
814.15:067:11
914.15:047:12
1014.25:037:13
1114.25:027:14
1214.25:017:15
1314.35:007:16
1414.34:597:17
1514.34:587:18
1614.44:577:19
1714.44:567:20
1814.44:557:21
1914.54:547:22
2014.54:537:23
2114.54:527:24
2214.64:517:25
2314.64:507:26
2414.64:497:27
2514.74:497:28
2614.74:487:29
2714.74:477:30
2814.74:477:31
2914.84:467:32
3014.84:457:32
3114.84:457:33

Solar energy in May

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in May, about 5.65 kWh/m².

For context, solar energy here swings from a low near 1.76 kWh/m² to a high of 6.44 kWh/m² in July across the year — May's 5.65 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
15.3Bright
25.3Bright
35.3Bright
45.3Bright
55.4Bright
65.4Bright
75.4Bright
85.5Bright
95.5Bright
105.5Bright
115.6Bright
125.6Bright
135.6Bright
145.7Bright
155.7Bright
165.7Bright
175.7Bright
185.8Bright
195.8Bright
205.8Bright
215.8Bright
225.8Bright
235.8Bright
245.8Bright
255.8Bright
265.8Bright
275.9Bright
285.9Bright
295.9Bright
305.9Bright
316.0Bright
Planning a trip in May

Is May a good time to visit Marshalltown?

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

6.0
Sightseeing
5th-best month of the year
3.8
Beach & pool
5th-best month of the year

May is a reasonable time to visit Marshalltown for sightseeing.

What to pack for Marshalltown in May

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

In May, Marshalltown sees daytime highs around 70°F and nights near 51°F. Worth packing: rain gear and sun protection. About 14 days see rain.

rain gearsun protection

UV index in Marshalltown 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 Marshalltown peaks around June 18 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJun 18UV 9Dec 21UV 2
UV index (midday)Level
Jan2Low
Feb3Moderate
Mar4Moderate
Apr6High
May7Very high
Jun9Very high
Jul8Very high
Aug8Very high
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Marshalltown in May

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where May falls, not just the annual average.

Air quality in Marshalltown is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (October, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

01020JanFebMarAprMayJunJulAugSepOctNovDecModerateGoodModerateGoodJul 1916 µg/m³Oct 218 µg/m³
PM2.5 (µg/m³)Level
Jan13Moderate
Feb15Moderate
Mar14Moderate
Apr11Good
May12Good
Jun13Moderate
Jul16Moderate
Aug15Moderate
Sep12Good
Oct7Good
Nov9Good
Dec10Good
Location & terrain

Where is Marshalltown?

Marshalltown sits at 42.0°N, 92.9°W, 942 ft above sea level, in United States. The nearest listed city is Newton, 25 mi away.

Topography around Marshalltown

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Marshalltown.

Within 2 miles, the terrain around Marshalltown has only modest variations in elevation — a maximum elevation change of 161 ft around an average of 902 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 266 ft; within 50 miles, only modest variations in elevation — a maximum elevation change of 620 ft.

The land around Marshalltown is covered by grassland (29%), artificial surfaces (29%) and trees (22%) within 2 miles, cropland (74%) within 10 miles, and cropland (80%) within 50 miles.

2 miles
161 ft
10 miles
266 ft
50 miles
620 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
May weather nearby: Newton 25 mi · Ames 37 mi · Altoona 40 mi · Cedar Falls 40 mi · Waterloo 42 mi · Ankeny 42 mi · Des Moines 48 mi · Johnston 48 mi

United States travel facts

Power plugs
Type A / B
120 V · 60 Hz
Prices
≈ 100% of US
price level, 2025
GDP per capita
$90,027
2025
Happiness
6.8 / 10
World Happiness, 2025
Safe drinking water
98%
of population, 2024
Homicide rate
5.8
per 100k, 2023
Road deaths
12.7
per 100k/yr, 2019
Income group
High
World Bank
Religion
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 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 Marshalltown (42.0494°, -92.908°, elevation 942 ft), 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. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).