Missing Data Frame Values

[meminens]

Daily snow data for KERI (72526) has some gaps in January 2018. However, these gaps are not NaN therefore the interpolate function does not close the gap. Here is a snippet of the data frame:

time,tavg,tmin,tmax,prcp,snow,wdir,wspd,wpgt,pres,tsun
2017-12-28,13.8,10.2,16.2,0.0,20.984,,5.8,,,
2017-12-29,12.7,8.2,19.2,0.272,20.0,,9.6,,,
2017-12-30,16.2,13.1,19.2,0.681,22.992,249.0,13.2,,,
2017-12-31,13.1,11.1,15.3,0.0,25.0,,7.8,,1029.6,
2018-01-01,14.2,12.2,15.3,0.02,,288.0,14.3,,,
2018-01-02,12.9,7.2,16.2,0.051,,216.0,16.3,,,
2018-01-03,11.7,5.2,21.2,0.012,,201.0,13.0,,,
2018-01-04,16.5,7.2,20.1,0.299,,,13.4,,,
2018-01-05,7.7,5.2,8.2,0.031,,294.0,13.4,,,
2018-01-06,6.6,5.2,9.1,0.0,,278.0,10.1,,,
2018-01-07,8.1,-0.8,29.1,0.0,,181.0,15.2,,1029.1,
2018-01-08,31.3,29.1,35.1,0.252,,211.0,16.1,,,
2018-01-09,32.2,23.2,34.0,0.0,,,8.5,,,
2018-01-10,32.5,24.3,48.0,0.0,,,15.9,,,
2018-01-11,50.9,46.9,61.0,0.091,0.0,170.0,19.7,,1015.3,
2018-01-12,48.0,18.1,57.9,0.831,0.0,292.0,13.4,,,
2018-01-13,16.7,13.1,18.1,0.031,3.937,,12.6,,,
2018-01-14,14.5,5.2,20.1,0.0,3.937,,4.7,,1038.4,
2018-01-15,14.2,10.2,25.2,0.051,3.15,,10.5,,,