Temperature seasonal cycles (degC) from Jones et al. (1999) dataset
See "Absolute 1961-1990" here: https://crudata.uea.ac.uk/cru/data/temperature/

Abs = absolute, Anom = anomaly from annual mean

             Global            NH                SH
 Month       Abs    Anom       Abs    Anom       Abs    Anom
 1 Jan    12.106  -1.867     7.889  -6.697    16.323   2.962
 2 Feb    12.248  -1.725     8.410  -6.176    16.087   2.726
 3 Mar    12.874  -1.100    10.570  -4.016    15.177   1.816
 4 Apr    13.862  -0.112    13.768  -0.818    13.955   0.594
 5 May    14.891   0.917    17.084   2.498    12.698  -0.663
 6 Jun    15.587   1.614    19.586   5.001    11.588  -1.773
 7 Jul    15.859   1.885    20.969   6.383    10.748  -2.613
 8 Aug    15.710   1.737    20.820   6.234    10.600  -2.761
 9 Sep    15.072   1.098    19.008   4.422    11.136  -2.225
10 Oct    14.087   0.113    15.796   1.210    12.377  -0.984
11 Nov    13.032  -0.942    12.010  -2.576    14.053   0.692
12 Dec    12.355  -1.618     9.120  -5.466    15.590   2.229

Annual    13.974            14.586            13.361