Winter nights in Grantham are colder than in 83% of UK towns
Midsummer highs settle at about 22.0°C (72°F). Seasons differ by 21°C, from the coldest nights to the warmest afternoons. It is a dry place: less rain falls here than on 79% of UK towns. Windscreens need scraping on about 44 mornings a year, the nights the air drops below 0°C.
Met Office 1991–2020 averages for the town itself.
A year in Grantham at a glance
Each month’s typical high and low, in °C.
What a year in Grantham feels like
Typical highs and lows by season and by month, from the Met Office’s 1991–2020 averages.
About 654 mm of rain a year
October is the wettest month and March the driest. About 14 days a year bring 10 mm (0.4 in) or more. 14th wettest of 64 Lincolnshire towns of 2,500+.
Rain by month
Millimetres
Sunshine by month
Hours of bright sunshine at Waddington
44 air frosts and 14 days of 25°C a year
On about 44 nights a year the air drops below freezing, and on about 1 days it stays below freezing all day. About 14 days a year reach 25°C (77°F).
Day counts are 1991–2020 averages from the Met Office’s 2 km grid. The Met Office calls a day of 25°C or more a summer day and a night below 0°C an air frost; ground frosts, on grass, come more often.
The Met Office station at Waddington
Waddington is 19 miles north of Grantham, 68 m (223 ft) above sea level. It is the nearest of the 37 long-running stations the Met Office publishes in full.
| Month | High | Low | Rain | Air frosts | Sun (hours) |
|---|---|---|---|---|---|
| January | 7.0°C | 1.6°C | 48 mm | 9.1 | 61 |
| February | 7.7°C | 1.7°C | 38 mm | 8.4 | 84 |
| March | 10.2°C | 3.0°C | 36 mm | 4.7 | 122 |
| April | 13.2°C | 4.9°C | 44 mm | 1.2 | 162 |
| May | 16.3°C | 7.6°C | 47 mm | 0.1 | 203 |
| June | 19.1°C | 10.5°C | 60 mm | 0.0 | 182 |
| July | 21.6°C | 12.7°C | 60 mm | 0.0 | 197 |
| August | 21.4°C | 12.6°C | 59 mm | 0.0 | 184 |
| September | 18.3°C | 10.5°C | 53 mm | 0.0 | 141 |
| October | 14.1°C | 7.6°C | 61 mm | 0.3 | 106 |
| November | 9.9°C | 4.3°C | 57 mm | 2.9 | 69 |
| December | 7.2°C | 2.0°C | 52 mm | 8.6 | 60 |
| Year | 13.8°C | 6.6°C | 616 mm | 35 | 1,571 |
Met Office historic station data, Waddington, 1991–2020 months averaged (a month needs 20 of the 30 years; estimated values counted, missing months left out). Sunshine: Kipp & Zonen recorder.
How Grantham compares
Against the 2,537 towns and cities of 2,500 or more across the UK, each with its own Met Office averages, and its place among Lincolnshire towns that size.
Nearby towns’ climate
The nearest towns of 1,000+ within 12 miles: a hill, a valley or the sea can make a real difference over a few miles.
| Town | July high | January low | Rain a year |
|---|---|---|---|
| Grantham | 22.0°C | 1.3°C | 654 mm |
| Great Gonerby 1.8 mi | 22.1°C about the same | 1.3°C about the same | 651 mm |
| Barrowby 1.9 mi | 22.0°C about the same | 1.2°C about the same | 656 mm |
| Bottesford 6.9 mi | 22.2°C about the same | 1.5°C about the same | 588 mm |
| Long Bennington 7.3 mi | 22.2°C about the same | 1.5°C about the same | 621 mm |
| Colsterworth 7.6 mi | 21.8°C about the same | 1.1°C about the same | 679 mm |
| Corby Glen 8.8 mi | 21.9°C about the same | 1.1°C about the same | 650 mm |
Grantham weather by month
Average daily high and low, mean temperature and rain, 1991–2020, for the town itself (the Met Office’s HadUK-Grid).
| Month | High | Low | Mean | Rain |
|---|---|---|---|---|
| January | 7.2°C 45°F | 1.3°C 34°F | 4.3°C | 51 mm 2.0 in |
| February | 7.8°C 46°F | 1.2°C 34°F | 4.5°C | 44 mm 1.7 in |
| March | 10.4°C 51°F | 2.5°C 36°F | 6.4°C | 41 mm 1.6 in |
| April | 13.4°C 56°F | 4.2°C 39°F | 8.8°C | 45 mm 1.8 in |
| May | 16.5°C 62°F | 6.9°C 44°F | 11.7°C | 49 mm 1.9 in |
| June | 19.5°C 67°F | 9.7°C 50°F | 14.6°C | 61 mm 2.4 in |
| July | 22.0°C 72°F | 11.8°C 53°F | 16.9°C | 60 mm 2.4 in |
| August | 21.7°C 71°F | 11.8°C 53°F | 16.7°C | 60 mm 2.4 in |
| September | 18.6°C 65°F | 9.6°C 49°F | 14.1°C | 55 mm 2.2 in |
| October | 14.3°C 58°F | 7.0°C 45°F | 10.6°C | 66 mm 2.6 in |
| November | 10.0°C 50°F | 3.7°C 39°F | 6.9°C | 60 mm 2.4 in |
| December | 7.3°C 45°F | 1.4°C 35°F | 4.4°C | 62 mm 2.4 in |
| Year | 14.0°C | 5.9°C | 10.0°C | 654 mm |
Where Grantham’s numbers come from
Averages over 30 years, not a forecast.
- Mean temperature, rain and day counts: HadUK-Grid 1991–2020 averages for the 1 Met Office 2 km grid square whose centre lies inside Grantham’s built-up area.
- Highs and lows: the Met Office publishes average daily maxima and minima on its 12 km grid; each is moved by the difference between the town’s 2 km mean temperature and the 12 km square’s, which carries the town’s own height and setting over.
- Weather station and sunshine: Met Office historic station data for Waddington, 19 miles away, months of 1991–2020 averaged.
- Comparisons: every town and city of 2,500 or more across the UK, all four nations, read the same way.
Met Office HadUK-Grid · Met Office Climate Data Portal · Historic station data. Open Government Licence v3.0.
Questions about Grantham’s climate
How warm does Grantham get in summer?
July is the warmest month, with average highs of 22.0°C (72°F). About 14 days a year reach 25°C (77°F), more than 67% of UK towns.
How cold does Grantham get in winter?
February nights average 1.2°C (34°F). The air drops below freezing on about 44 nights a year, and about 1 days a year stay below freezing all day.
How much rain does Grantham get?
About 654 mm (26 in) a year, less than 79% of UK towns. October is the wettest month (66 mm) and March the driest (41 mm).
How sunny is it?
The nearest Met Office station with a sunshine record, Waddington (19 miles away), averages 1,571 hours of bright sunshine a year. Sunshine isn’t on the town grid, so this is the station’s figure.
Where do these figures come from?
The Met Office’s HadUK-Grid 1991–2020 averages, which turn thousands of weather stations into a map of the UK in 2 km squares; the page reads the squares inside Grantham. They are 30-year averages, not a forecast.
Contains Met Office data © Crown copyright 2026, Open Government Licence v3.0. HadUK-Grid 1991–2020 averages via the Met Office Climate Data Portal; station averages from Met Office historic station data. Today’s forecast for Grantham →
Contains public sector information licensed under the Open Government Licence v3.0. Contains HM Land Registry data © Crown copyright and database right 2026. Contains OS data © Crown copyright and database right 2026 (ONS boundaries). Northern Ireland: Source: NISRA; contains Land & Property Services data and Ordnance Survey of Northern Ireland information, © Crown copyright, licensed under the Open Government Licence v3.0. Scotland: contains National Records of Scotland data, Registers of Scotland data and SEPA data, © Crown copyright / © SEPA 2025, licensed under the Open Government Licence v3.0.