Grantham weather in August

In August, Grantham sees average daytime highs of 21°C and overnight lows near 13°C, with 65 mm of rain across 11 wet days and about 14.5 hours of daylight. It is the 2nd-warmest and 1st-wettest month of the year here.

Highs ease over the month, from about 22°C in the first days to 20°C by the end. The sky is clear or mostly clear about 12% of the time in August, and the air most often feels dry.

Daylight stretches from about 15 h 24 min at the start of August to 13 h 30 min by month's end. Set against the rest of the year, August is Grantham's 1st-clearest and 10th-windiest month. For the whole year in context, see Grantham's year-round climate.

Daytime high
21°
2nd warmest
Overnight low
13°
11th coldest
Rainfall
65 mm
11 wet days
Daylight
14 h 30 min
4:50 AM – 7:23 PM
Cloud cover
70%
1st clearest
Wind
14 km/h
10th windiest
Solar energy
4.05 kWh/m²
Travel score
6.1
out of 10

Grantham is market town and civil parish in South Kesteven, Lincolnshire, England.

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

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 22°C in the first days to 20°C by the end.

A typical August day in Grantham reaches about 21°C in the afternoon and slips back to 13°C overnight — a 8°C spread between the day's warmth and the night's chill. On most days the high lands between 18°C and 25°C. Set against its neighbours, August runs on par with July and about 3°C warmer than September.

10°15°20°25°30°151015202531
Avg high (°C)Avg low (°C)
12213
22213
32213
42213
52213
62213
72213
82213
92213
102213
112213
122113
132113
142113
152113
162113
172113
182113
192113
202113
212113
222112
232112
242012
252012
262012
272012
282012
292012
302012
312012

How August really feels in Grantham

Once humidity and wind are folded in, August 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

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

Grantham weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 1st-wettest month here — the current month is highlighted below.

MonthHigh / Low (°C)Rainfall (mm)Wet daysSnow daysDaylight (hours)Travel score
Jan / 4811.31.17.90.8
Feb / 389.51.49.51.2
Mar10° / 4410.20.911.52.2
Apr13° / 5111.10.213.63.4
May16° / 5310.8015.54.7
Jun19° / 11°6411.3016.65.6
Jul21° / 13°6310.9016.16.2
Aug21° / 13°6511014.56.1
Sep18° / 10°549.4012.45.7
Oct14° / 6010.9010.33.9
Nov10° / 56110.28.42.1
Dec / 5311.11.17.41.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 12% of the time in August, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 21% of August, with mostly cloudy or overcast conditions the remaining 67%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
13466
23466
33466
43565
53565
63565
73565
83565
93565
103565
113565
123565
133466
143466
153367
163367
173367
183367
193268
203268
213268
223268
233169
243169
253169
263070
272971
283070
293070
303070
313070

Chance of precipitation in August

Any precipitation

Grantham gets around 65 mm of rain over 11 wet days in August, the wettest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 36% and peaks near 38% on the wettest days.

0%10%20%30%40%50%151015202531
Rain chance (%)
137
237
337
437
536
636
736
836
935
1035
1135
1235
1336
1436
1536
1637
1737
1837
1938
2038
2137
2237
2337
2436
2535
2635
2734
2833
2932
3032
3131

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the dry band about 65% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
158339
259329
359329
459329
559329
659329
760319
860319
960319
1060319
1161309
1261309
1361309
1461309
1562308
1663298
1763298
1863298
1965287
2066277
2167276
2268266
2369256
2470255
2571245
2672244
2773234
2873234
2974233
3075223
3175223

Wind in August

Winds average 14 km/h in August.

Across August, 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.

05101520151015202531
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
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
3115light breeze

Sunrise & sunset in August

DaylightNight

Daylight runs from about 15 h 24 min at the start of August to 13 h 30 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 114 minutes over August. Sunrise moves from 4:25 AM to 5:17 AM, and sunset from 7:52 PM to 6:49 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
115.44:257:52
215.44:277:50
315.34:297:48
415.34:307:47
515.24:327:45
615.24:337:43
715.14:357:41
815.04:377:39
915.04:397:37
1014.94:407:35
1114.94:427:33
1214.84:447:31
1314.74:457:29
1414.74:477:27
1514.64:497:25
1614.54:507:23
1714.54:527:21
1814.44:547:19
1914.34:567:16
2014.34:577:14
2114.24:597:12
2214.15:017:10
2314.15:037:07
2414.05:047:05
2513.95:067:03
2613.95:087:00
2713.85:106:58
2813.75:116:56
2913.75:136:53
3013.65:156:51
3113.55:176:49

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 4.05 kWh/m².

For context, solar energy here swings from a low near 0.58 kWh/m² to a high of 4.95 kWh/m² in June across the year — August's 4.05 kWh/m² falls in the middle.

024151015202531
Solar energy (kWh/m²)Level
14.5Bright
24.5Bright
34.5Bright
44.5Bright
54.4Bright
64.4Bright
74.4Bright
84.3Bright
94.3Bright
104.3Bright
114.3Bright
124.2Bright
134.2Bright
144.2Bright
154.1Bright
164.1Bright
174.0Bright
184.0Bright
194.0Moderate
203.9Moderate
213.9Moderate
223.9Moderate
233.8Moderate
243.8Moderate
253.7Moderate
263.7Moderate
273.6Moderate
283.6Moderate
293.6Moderate
303.5Moderate
313.5Moderate
Planning a trip in August

Is August a good time to visit Grantham?

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

6.1
Sightseeing
2nd-best month of the year
3.7
Beach & pool
2nd-best month of the year

August is a reasonable time to visit Grantham for sightseeing.

What to pack for Grantham in August

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

In August, Grantham sees daytime highs around 21°C and nights near 13°C. Worth packing: rain gear. About 11 days see rain.

rain gear

Sea temperature near Grantham in August

The nearest coast averages about 18°C in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 68 km away) is warmest in August at about 18°C and coldest in February near 5°C.

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

5°10°15°20°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°C)Comfort
Jan6Bracing
Feb5Bracing
Mar6Bracing
Apr8Bracing
May11Bracing
Jun14Bracing
Jul17Cool
Aug18Cool
Sep16Cool
Oct13Bracing
Nov10Bracing
Dec7Bracing

UV index in Grantham in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Grantham peaks around August 11 at about 6 (high) — sunscreen and a hat are worth it in the middle of the day. 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 6 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighModerateLowAug 11UV 6Jan 1UV 1
UV index (midday)Level
Jan1Low
Feb1Low
Mar3Moderate
Apr3Moderate
May5High
Jun6High
Jul6High
Aug6High
Sep4Moderate
Oct2Low
Nov1Low
Dec1Low
Location & terrain

Where is Grantham?

Grantham sits at 52.9°N, 0.6°W, 64 m above sea level, in United Kingdom. The nearest listed city is Sleaford, 18 km away.

Topography around Grantham

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

Within 3 km, the terrain around Grantham has only modest variations in elevation — a maximum elevation change of 90 m around an average of 84 m above sea level; within 16 km, only modest variations in elevation — a maximum elevation change of 170 m; within 80 km, significant variations in elevation — a maximum elevation change of 494 m.

The land around Grantham is covered by cropland (31%), artificial surfaces (26%) and trees (22%) within 3 km, cropland (66%) and grassland (21%) within 16 km, and cropland (53%) and grassland (25%) within 80 km.

3 km
90 m
16 km
170 m
80 km
494 m
treesgrasslandcroplandartificial surfaceswater
August weather nearby: Sleaford 18 km · Newark on Trent 21 km · Melton Mowbray 23 km · Stamford 31 km · West Bridgford 32 km · Arnold 34 km · Nottingham 34 km · Spalding 36 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 Grantham (52.9115°, -0.6418°, elevation 64 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).