All nightly seeing data at Paranal or at La Silla can be publicly retrieved from the ambient server in ASCII format by adding &data=S at the end of the link, e.g.:

http://archive.eso.org/asm/ambient-server?site=paranal&night=2009-11-01&data=S

http://archive.eso.org/asm/ambient-server?site=lasilla&night=2009-11-01&data=S

The data parameter accepts different values, which in turn make the service return different ambient parameters:

&data=S for Seeing (arcsec)
&data=T for Temperature (C)
&data=H for relative Humidity (%)
&data=P for atmospheric Pressure (hPa)
&data=W for Wind speed (m/s)
&data=E for relative flux root-mean-square Error (adimensional)
&data=R for coheRence time tau0 (ms)
&data=TETA0 for anisoplanatic Theta angle (arcsec)

Note that the rows are in inverse chronological order, with time-stamps in MJD (take fractional part, remove 0.5 and multiply by 24 to get hour UT).

Should you need more than one night of data, it is relatively straightforward to use curl or shell programming with curl or wget to get date ranges.