Click on a day for an hourly weather forecast
The temperatures in Grantham in August are comfortable with low of 13°C and and high up to 21°C.
You can expect about 3 to 8 days of rain in Grantham during the month of August. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Grantham in August 2025.
If you’re planning to visit Grantham in the near future, we highly recommend that you review the 14 day weather forecast for Grantham before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 6° / 1° | 7 | 20 | 5 | 46 mm | Awful | Grantham in January |
| February | 7° / 2° | 6 | 16 | 6 | 44 mm | Bad | Grantham in February |
| March | 10° / 3° | 6 | 23 | 2 | 44 mm | Bad | Grantham in March |
| April | 13° / 4° | 4 | 26 | 1 | 37 mm | Ok | Grantham in April |
| May | 15° / 7° | 6 | 25 | 0 | 62 mm | Good | Grantham in May |
| June | 18° / 10° | 5 | 25 | 0 | 75 mm | Good | Grantham in June |
| July | 21° / 12° | 4 | 27 | 0 | 64 mm | Good | Grantham in July |
| August | 21° / 13° | 5 | 26 | 0 | 65 mm | Good | Grantham in August |
| September | 18° / 11° | 3 | 27 | 0 | 40 mm | Good | Grantham in September |
| October | 14° / 8° | 5 | 26 | 0 | 59 mm | Good | Grantham in October |
| November | 10° / 5° | 7 | 23 | 0 | 53 mm | Bad | Grantham in November |
| December | 7° / 3° | 6 | 21 | 3 | 52 mm | Bad | Grantham in December |