Found this table in my archives of the mean temperatures recorded at Greenwich from 15th February to 16th March for the years 1814-1878. I have converted them into Celsius

1814: -1.0C
1815: 6.2C
1816: 4.4C
1817: 5.7C
1818: 4.3C
1819: 4.6C
1820: 2.8C
1821: 3.6C
1822: 6.8C
1823: 3.7C
1824: 4.1C
1825: 4.3C
1826: 7.1C
1827: 3.7C
1828: 6.3C
1829: 3.2C
1830: 5.3C
1831: 5.8C
1832: 2.4C
1833: 3.7C
1834: 7.7C
1835: 5.0C
1836: 2.8C
1837: 3.8C
1838: 3.3C
1839: 2.9C
1840: 2.0C
1841: 6.2C
1842: 5.9C
1843: 3.2C
1844: 3.8C
1845: 0.1C
1846: 7.9C
1847: 3.9C
1848: 5.5C
1849: 6.6C
1850: 6.5C
1851: 4.4C
1852: 3.7C
1853: 2.8C
1854: 5.8C
1855: 1.2C
1856: 3.9C
1857: 5.1C
1858: 1.4C
1859: 7.9C
1860: 1.3C
1861: 6.7C
1862: 5.4C
1863: 5.4C
1864: 3.8C
1865: 3.2C
1866: 2.6C
1867: 4.1C
1868: 7.1C
1869: 4.2C
1870: 3.7C
1871: 6.3C
1872: 7.5C
1873: 3.2C
1874: 3.8C
1875: 2.7C
1876: 7.0C
1877: 4.4C
1878: 7.6C
The standout figure there is the 1814 figure with -1.0C

Ranked in terms of coldness

1814: -1.0C
1845: 0.1C
1855: 1.2C
1860: 1.3C
1858: 1.4C
1840: 2.0C
1832: 2.4C
1866: 2.6C
1875: 2.7C
1820: 2.8C
1836: 2.8C
1853: 2.8C
1839: 2.9C
1829: 3.2C
1873: 3.2C
1843: 3.2C
1865: 3.2C
1838: 3.3C
1821: 3.6C
1823: 3.7C
1827: 3.7C
1833: 3.7C
1852: 3.7C
1870: 3.7C
1837: 3.8C
1844: 3.8C
1864: 3.8C
1874: 3.8C
1847: 3.9C
1856: 3.9C
1824: 4.1C
1867: 4.1C
1869: 4.2C
1818: 4.3C
1825: 4.3C
1816: 4.4C
1851: 4.4C
1877: 4.4C
1819: 4.6C
1835: 5.0C
1857: 5.1C
1830: 5.3C
1862: 5.4C
1863: 5.4C
1848: 5.5C
1817: 5.7C
1831: 5.8C
1854: 5.8C
1842: 5.9C
1815: 6.2C
1841: 6.2C
1828: 6.3C
1871: 6.3C
1850: 6.5C
1849: 6.6C
1861: 6.7C
1822: 6.8C
1876: 7.0C
1826: 7.1C
1868: 7.1C
1872: 7.5C
1878: 7.6C
1834: 7.7C
1846: 7.9C
1859: 7.9C

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