http://www.mtu.edu/alumni/favorites/snowfall/snowfall.html

sunspots:
http://solarscience.msfc.nasa.gov/greenwch/spot_num.txt
http://solarscience.msfc.nasa.gov/greenwch/SN_m_tot_V2.0.txt
http://www.sidc.be/silso/datafiles
http://www.sidc.be/silso/DATA/SN_d_tot_V2.0.txt


Mean temp/precip/etc:
http://w2.weather.gov/climate/xmacis.php?wfo=mqt

Note 1890 temp values were missing; replaced with mean for month 10 years after.

Ice cover data (from 1973 on)
https://coastwatch.glerl.noaa.gov/statistic/statistic.html
https://www.glerl.noaa.gov/data/ice/#historical
https://www.glerl.noaa.gov/data/ice/dates_AMIC.txt


El Nino Activity:
http://www.bom.gov.au/climate/current/soihtm1.shtml