Warmest month
- Jamestown
- March · 23.60 °C
- London
- July · 18.57 °C
Jamestown (Saint Helena, Ascension and Tristan da Cunha) vs London (Great Britain): Temperature, Rainfall and Sunshine
Reference period: Jamestown 2013–2023 · London 2013–2023
Jamestown (Saint Helena, Ascension and Tristan da Cunha) has a higher monthly mean temperature than London (Great Britain) in every month of the year.
Key monthly differences
Coolest month
- Jamestown
- September · 18.93 °C
- London
- January · 4.73 °C
Driest month
- Jamestown
- November · 0.36 mm/day
- London
- April · 1.33 mm/day
Sunniest month
- Jamestown
- January · 11.76 hours/day
- London
- July · 10.94 hours/day
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Climate comparison questions
When are the temperatures most similar and most different?
The smallest difference in monthly mean temperature is 1.30 °C (July); the largest is 17.83 °C (February).
How much do temperatures vary across the year?
The difference between the warmest and coolest monthly means is 4.67 °C in Jamestown (Saint Helena, Ascension and Tristan da Cunha) and 13.84 °C in London (Great Britain). This describes seasonal variation, not the range between daytime highs and nighttime lows.
Which location has more rainfall?
Jamestown (Saint Helena, Ascension and Tristan da Cunha) has a higher daily rainfall average in 0 months and London (Great Britain) in 12; 0 months are equal at the displayed precision. Rainfall amounts do not tell us how many days it rains.
Which location has more sunshine?
Jamestown (Saint Helena, Ascension and Tristan da Cunha) has more average sunshine hours per day in 9 months and London (Great Britain) in 3; 0 months are equal at the displayed precision. Sunshine duration is different from daylight duration.
Climate data notes
Show data and calculation
Daily values are averaged separately for each calendar month over the saved reference period. Temperatures are daily means, not daytime highs. Rainfall is an average daily amount, not a monthly total; sunshine is average hours per day. These historical averages are not a weather forecast. Each location’s reference period is listed below and may differ.
Mean of the 12 monthly averages
Monthly climate data
Difference: London (Great Britain) minus Jamestown (Saint Helena, Ascension and Tristan da Cunha)
Temperature °C
| Month | Jamestown | London | +/- |
|---|---|---|---|
| Jan | 22.20 | 4.73 | −17.47 |
| Feb | 23.27 | 5.44 | −17.83 |
| Mar | 23.60 | 6.84 | −16.76 |
| Apr | 23.19 | 9.18 | −14.00 |
| May | 22.26 | 12.67 | −9.59 |
| Jun | 20.96 | 16.27 | −4.69 |
| Jul | 19.87 | 18.57 | −1.30 |
| Aug | 19.19 | 17.74 | −1.45 |
| Sep | 18.93 | 15.48 | −3.45 |
| Oct | 19.03 | 12.31 | −6.72 |
| Nov | 19.72 | 8.09 | −11.63 |
| Dec | 20.81 | 6.52 | −14.29 |
| Annual mean | 21.08 | 11.15 | −9.93 |
Average sunshine (hours/day)
| Month | Jamestown | London | +/- |
|---|---|---|---|
| Jan | 11.76 | 3.74 | −8.02 |
| Feb | 11.45 | 5.11 | −6.34 |
| Mar | 10.93 | 6.38 | −4.55 |
| Apr | 10.63 | 9.22 | −1.41 |
| May | 10.24 | 10.11 | −0.13 |
| Jun | 9.78 | 10.51 | +0.74 |
| Jul | 9.68 | 10.94 | +1.26 |
| Aug | 9.62 | 9.68 | +0.06 |
| Sep | 9.99 | 8.02 | −1.97 |
| Oct | 10.29 | 5.86 | −4.43 |
| Nov | 11.14 | 4.12 | −7.02 |
| Dec | 11.65 | 3.14 | −8.50 |
| Annual mean | 10.60 | 7.24 | −3.36 |
Average daily rainfall (mm/day)
| Month | Jamestown | London | +/- |
|---|---|---|---|
| Jan | 0.46 | 1.92 | +1.46 |
| Feb | 0.44 | 1.71 | +1.27 |
| Mar | 0.60 | 1.61 | +1.00 |
| Apr | 0.48 | 1.33 | +0.85 |
| May | 0.47 | 1.85 | +1.38 |
| Jun | 0.58 | 1.93 | +1.35 |
| Jul | 0.61 | 1.79 | +1.18 |
| Aug | 0.51 | 2.02 | +1.51 |
| Sep | 0.48 | 1.61 | +1.13 |
| Oct | 0.39 | 2.51 | +2.12 |
| Nov | 0.36 | 2.27 | +1.91 |
| Dec | 0.51 | 2.10 | +1.60 |
| Annual mean | 0.49 | 1.89 | +1.40 |
Snow (mm)
| Month | Jamestown | London | +/- |
|---|---|---|---|
| Jan | 0.00 | 0.94 | +0.94 |
| Feb | 0.00 | 0.76 | +0.76 |
| Mar | 0.00 | 0.77 | +0.77 |
| Apr | 0.00 | 0.05 | +0.05 |
| May | 0.00 | 0.00 | 0.00 |
| Jun | 0.00 | 0.00 | 0.00 |
| Jul | 0.00 | 0.00 | 0.00 |
| Aug | 0.00 | 0.00 | 0.00 |
| Sep | 0.00 | 0.00 | 0.00 |
| Oct | 0.00 | 0.00 | 0.00 |
| Nov | 0.00 | 0.04 | +0.04 |
| Dec | 0.00 | 0.40 | +0.40 |
| Annual mean | 0.00 | 0.25 | +0.25 |
