As the year draws to a close, let's look back at what the weather's been doing. Not because it's something we all want to reminisce over, but because I reckon it's interesting to see what a full year's weather looks like.
The tables below show the weather for each day in 2020, grouped into categories and totted up by month. Yes, there are still four days to go, so I've used the forecast to predict the rest, and I'll come back later to update speculation with fact. I've blanked out the background of every empty cell to make the pattern of the coloured data stand out more. I've also emboldened any tally that enters double figures, making the general trend a bit easier to follow.
This is data from a weather station in Hampstead, so won't perfectly reflect your experience, nor the national picture. But it does present an intriguing picture of the twelve months gone by, and in a year of lockdown the weather's never been more/less important.
Maximum daily temperature, Hampstead, 2020
J
F
M
A
M
J
J
A
S
O
N
D
35-40°C
1
1
30-35°C
3
5
25-30°C
5
1
6
4
3
20-25°C
10
12
12
19
15
13
15-20°C
2
10
9
13
5
5
11
13
4
10-15°C
15
17
16
9
5
1
1
3
18
18
12
5-10°C
16
12
13
1
8
11
0-5°C
8
This is what the rise and fall of the year's maximum temperatures looks like. What stands out here are the two days when the mercury topped thirty-five degrees - on consecutive Fridays no less. This is not normal, indeed 35°C has only been exceeded at Hampstead on one other occasion in the last decade, which was last summer. The temperature in London topped 30° on ten separate occasions and exceeded 25° on 29, so 2020 had plenty of short-sleeve weather to go round. The true outliers were April and May which were much milder than usual, but also wasted because most of the time we were confined to our homes. Only eight days (all of them this month) failed to reach 5°C, and there's not a single occurrence of temperatures remaining below freezing all day (which is the joy of the inner London heat island effect).
Minimum daily temperature, Hampstead, 2020
J
F
M
A
M
J
J
A
S
O
N
D
20-25°C
2
15-20°C
4
6
19
4
10-15°C
1
2
11
22
21
9
16
9
4
1
5-10°C
20
12
8
21
14
5
4
1
10
22
16
11
0-5°C
9
17
22
6
6
10
14
-5-0°C
2
1
5
Minimum temperatures show a similar rise and fall through the course of a year, but within a narrower range. Thirty-five days this year had nights exceeding 15°C - ideal for sitting outside - including two rare 'tropical nights' in August when the temperature didn't drop below 20°C. We may see more of these in future. This year's cold snaps were in mid-January, late March and December, especially late December, with New Year's Eve the coldest day of the year. On only eight nights did the temperature dip below freezing (anywhere outside central London will likely have had rather more).
Hours of sunshine, Hampstead, 2020
J
F
M
A
M
J
J
A
S
O
N
D
12-15hr
10
14
6
4
1
2
8-11hr
4
2
9
9
8
5
8
9
9
1
5-7hr
3
6
1
5
5
3
7
10
6
1
1
2-4hr
11
12
7
7
3
5
7
7
3
12
13
9
0-1hr
6
8
5
2
1
7
6
4
4
4
1
3
0hr
10
4
4
1
2
3
3
2
9
14
18
Sunshine is where all the records were. May was the sunniest calendar month ever recorded (an accolade that'd normally be taken by June or July when the sun's above the horizon for longer). April was almost as good, a pairing which helped make this the sunniest spring on record (again totally wasted unless you were out on your daily exercise). From the start of lockdown to the end of May, somewhat cruelly, only one day was fully overcast. The summer months, though statistically more normal, could not compete. Meanwhile the last three months of the year have been particularly disappointing, with barely two-thirds of the expected level of sunshine and over half the year's complement of entirely dull days.
Daily rainfall, Hampstead, 2020
J
F
M
A
M
J
J
A
S
O
N
D
>20mm
3
10-20mm
1
1
1
1
2
1
1
5-10mm
3
7
1
1
1
2
2
4
1
4
1-5mm
7
5
6
2
1
4
7
4
6
10
8
10
0-1mm
6
8
6
3
1
9
5
4
2
6
10
7
0mm
15
8
17
23
29
15
17
19
22
7
11
9
It doesn't rainthat often in London, with over 50% of days this year (the bottom row) completely dry. Even most of the wet days weren't that wet - fewer than forty days exceeded 5mm. As for relentlessly wet days, only eleven times did Hampstead's rain gauge top 10mm. But October was a total washout, including three consecutive days which proved to be 2020's wettest, each with more than 20mm of rainfall. February was the other unusually wet month, dampening our final pre-lockdown weeks, and then of course we had the driest May on record with Hampstead enjoying twenty-nine completely dry days. It felt like 2020 was really toying with us, precipitation-wise.
Extreme weather, Hampstead, 2020
J
F
M
A
M
J
J
A
S
O
N
D
Fog
1
Hail
1
1
Thunder
2
1
3
5
Frost
2
1
5
Snow
1
Finally, still based on observations in Hampstead, a look at some of the more unusual meteorological conditions. Fog only descended briefly in February, while hail fell for the first time since 2017. As for thunder this rumbled during spring and summer about as often as it normally does. Air frost bookended the year, with one horticulturally-annoying outlier in early April. The year's entire complement of snow fell, unmemorably, on a single morning in February.
All in all 2020's weather has been fairly ordinary with a few extraordinary exceptions. Here's to more typically atypical weather in 2021.
