If you are looking to improve this winter the most important thing you can do is be in a sport and/or lift weights. In addition, there are some winter track camp opportunities.
Winter Training Camps for Track & Field
UW-Platteville All-American Camp (1/11 - 1/12): https://letsgopioneers.com/sports/track/camps2024
UW-La Crosse Camp of Champs (2/16, 2/23, 3/02): https://trackandfield.uwlcamps.com/index.cfm
UW-Oshkosh Track & Field Camps (1/12, 3/02, 3/09):
https://track.uwoshkoshsportscamps.com/
Ripon Redhawk Track & Field Camps (12/09 and 1/11):
https://riponredhawks.com/sports/2024/10/15/2024-25-track-camps.aspx
UW-Whitewater Learn by Doing Track & Field Camp (2/16): https://www.uww.edu/ce/camps/athletic/track_field
UW River Falls Track Pass (Sundays - 1/19-3/2):
http://www.uwrftrackandfieldcamps.com/index.php
UW-Stout XC/Track & Field Camps (1/7-2/18):
https://stoutbluedevils.com/sports/2023/7/27/xc-track-and-field-youth-camp.aspx