Days of the week

I agree with Tolley that the best (and safest) way of presenting these would be to spell them out – especially the second example. Here are some options for abbreviation:

Chicago Manual of Style (16th edn., 2010) – 10.41, p. 503

Days of the week. Where space restrictions require that days of the week be abbreviated, one of the following systems is often used. The second (common in computer code) and third use no periods. In formal prose, Chicago recommends the first.

Sun. or Sun or Su

Mon. or Mon or M

Tues. or Tue or Tu

Wed. or Wed or W

Thurs. or Thu or Th

Fri. or Fri or F

Sat. or Sat or Sa

The Associated Press Stylebook and Briefing on Media Law 2011 – p. 80

Days of the week

Capitalize them. Do not abbreviate, except when needed in tabular format: Sun, Mon, Tue, Wed, Thu, Fri, Sat (three letters, without periods to facilitate tabular composition).

MLA Handbook for Writers of Research Papers (7th edn., 2009) – 7.2, p. 235

Time Designations

Sun. Mon. Tues. Wed. Thurs. Fri. Sat.

New Hart's Rules (aka Oxford Style Manual)(2005) – 10.2.6, p. 172 (for GB and international English)

Names of days and months should generally be shown in full, but where necessary, as in notes and in order to save space, they are abbreviated thus:

Sun. Mon. Tue. Wed. Thur. Fri. Sat.

I recommend:

Mon.–Thurs.

Mon., Wed., & Thurs., weekly.