Aliases: daylength
Keywords: spatial
### ** Examples daylength(-25, '2010-10-10')
[1] 12.51875
daylength(45, 1:365)
[1] 8.826005 8.839717 8.854701 8.870943 8.888425 8.907131 8.927040 [8] 8.948135 8.970393 8.993795 9.018317 9.043937 9.070632 9.098378 [15] 9.127151 9.156925 9.187676 9.219378 9.252006 9.285533 9.319935 [22] 9.355186 9.391259 9.428128 9.465770 9.504157 9.543265 9.583070 [29] 9.623545 9.664668 9.706414 9.748760 9.791683 9.835159 9.879168 [36] 9.923687 9.968694 10.014171 10.060095 10.106448 10.153210 10.200363 [43] 10.247888 10.295769 10.343987 10.392527 10.441373 10.490509 10.539920 [50] 10.589592 10.639511 10.689662 10.740034 10.790614 10.841389 10.892348 [57] 10.943480 10.994773 11.046217 11.097802 11.149519 11.201357 11.253308 [64] 11.305363 11.357513 11.409751 11.462067 11.514456 11.566908 11.619417 [71] 11.671976 11.724578 11.777216 11.829884 11.882575 11.935282 11.988001 [78] 12.040724 12.093445 12.146159 12.198860 12.251541 12.304197 12.356822 [85] 12.409410 12.461955 12.514451 12.566891 12.619271 12.671583 12.723821 [92] 12.775979 12.828050 12.880028 12.931905 12.983674 13.035328 13.086860 [99] 13.138262 13.189526 13.240643 13.291605 13.342405 13.393031 13.443476 [106] 13.493730 13.543782 13.593623 13.643241 13.692627 13.741768 13.790653 [113] 13.839270 13.887607 13.935650 13.983387 14.030804 14.077887 14.124621 [120] 14.170991 14.216983 14.262581 14.307768 14.352528 14.396844 14.440700 [127] 14.484076 14.526955 14.569319 14.611149 14.652425 14.693128 14.733238 [134] 14.772735 14.811599 14.849809 14.887344 14.924183 14.960304 14.995687 [141] 15.030310 15.064150 15.097187 15.129399 15.160764 15.191262 15.220869 [148] 15.249566 15.277332 15.304145 15.329986 15.354835 15.378672 15.401478 [155] 15.423234 15.443924 15.463529 15.482033 15.499421 15.515677 15.530788 [162] 15.544739 15.557519 15.569116 15.579521 15.588723 15.596714 15.603488 [169] 15.609038 15.613359 15.616448 15.618303 15.618921 15.618303 15.616450 [176] 15.613363 15.609047 15.603507 15.596747 15.588774 15.579598 15.569226 [183] 15.557668 15.544937 15.531044 15.516002 15.499824 15.482527 15.464125 [190] 15.444634 15.424073 15.402457 15.379807 15.356140 15.331475 15.305834 [197] 15.279235 15.251700 15.223249 15.193904 15.163685 15.132614 15.100712 [204] 15.068001 15.034504 15.000240 14.965232 14.929502 14.893069 14.855957 [211] 14.818185 14.779774 14.740744 14.701116 14.660910 14.620146 14.578841 [218] 14.537016 14.494689 14.451878 14.408600 14.364874 14.320716 14.276142 [225] 14.231169 14.185813 14.140088 14.094010 14.047593 14.000851 13.953798 [232] 13.906448 13.858812 13.810903 13.762734 13.714316 13.665661 13.616779 [239] 13.567680 13.518376 13.468876 13.419190 13.369326 13.319294 13.269102 [246] 13.218759 13.168274 13.117652 13.066903 13.016034 12.965051 12.913963 [253] 12.862774 12.811493 12.760125 12.708676 12.657153 12.605562 12.553908 [260] 12.502198 12.450436 12.398629 12.346782 12.294900 12.242989 12.191055 [267] 12.139102 12.087137 12.035164 11.983190 11.931220 11.879259 11.827313 [274] 11.775388 11.723490 11.671626 11.619800 11.568021 11.516293 11.464625 [281] 11.413022 11.361493 11.310045 11.258684 11.207420 11.156260 11.105213 [288] 11.054288 11.003494 10.952841 10.902337 10.851995 10.801824 10.751835 [295] 10.702040 10.652451 10.603079 10.553939 10.505042 10.456404 10.408038 [302] 10.359958 10.312180 10.264721 10.217595 10.170820 10.124414 10.078393 [309] 10.032777 9.987584 9.942834 9.898547 9.854743 9.811443 9.768669 [316] 9.726443 9.684786 9.643723 9.603277 9.563470 9.524327 9.485874 [323] 9.448133 9.411131 9.374893 9.339443 9.304809 9.271014 9.238086 [330] 9.206050 9.174932 9.144757 9.115551 9.087338 9.060144 9.033993 [337] 9.008910 8.984917 8.962037 8.940294 8.919708 8.900300 8.882090 [344] 8.865098 8.849340 8.834834 8.821596 8.809640 8.798980 8.789627 [351] 8.781592 8.774885 8.769514 8.765485 8.762802 8.761470 8.761491 [358] 8.762865 8.765590 8.769665 8.775086 8.781846 8.789939 8.799356 [365] 8.810088
# average monthly daylength dl <- daylength(45, 1:365) tapply(dl, rep(1:12, c(31,28,31,30,31,30,31,31,30,31,30,31)), mean)
1 2 3 4 5 6 7 8
9.195859 10.378608 11.883299 13.461141 14.822720 15.547842 15.241914 14.080261
9 10 11 12
12.577470 11.009285 9.607862 8.841716