I was going to include Cille's stage win, first for today (it was on a 22nd), then for the women's edition, and then I gave up with the women's edition due to three - three! - major races all having happening on 25ths! And also the fact that WWT races seems to be mainly VDB, Van Vleuten, and Vos.
As for lots of Giro; well... it just covered the dates needed nicely.
Three and a half in fact, as De Panne was also on a 25th and is a WWT race. Vollering and Balsamo could be covered off elsewhere, though, whereas Brown and Kiesenhofer couldn't, and Kiesenhofer's win is the bigger of the two even though Brown is the higher profile rider. And the variety is not helped by some of women's cycling's major names not winning a race in 2021 (Niewiadoma, most notably).
I tried, OK?
1: Emma Norsgaard Jørgensen, GP Elsy Jacobs stage 1 (1/5)
2: Lizzie Deignan, Paris-Roubaix (2/10)
3: Anna van der Breggen, Giro d'Italia Donne stage 2 (3/7)
4: Annemiek van Vleuten, Ronde van Vlaanderen (4/4)
5: Lotte Kopecky, Ceratizit Challenge stage 4 (5/9)
6: Demi Vollering, The Women's Tour stage 3 (6/10)
7: Sandra Alonso, Vuelta Comunitat Valenciana stage 1 (7/5)
8: Lisa Klein, Baloise Ladies' Tour prologue (8/7)
9: Elisa Balsamo, The Women's Tour stage 6 (9/10)
10: Ashleigh Moolman-Pasio, Giro d'Italia Donne stage 9 (10/7)
11: Ruth Winder, Tour de l'Ardêche stage 4 (11/9)
12: Lonneke Uneken, Healthy Ageing Tour stage 3 (12/3)
13: Riejanne Markus, Ladies' Tour of Norway stage 2 (13/8)
14: Arlenis Sierra, Clásica Feminina de Navarra (14/5)
15: Chloe Hosking, Ladies' Tour of Norway stage 4 (15/8)
16: Chiara Consonni, GP Plumelec (16/10)
17: Marlen Reusser, Chrono des Nations (17/10)
18: Marianne Vos, Amstel Gold Race (18/4)
19: Lucinda Brand, Citadelcross (19/12)
20: Ellen van Dijk, World Championships ITT (20/9)
21: Elisa Longo Borghini, Trofeo Alfredo Binda (21/3)
22: Cecilie Uttrup Ludwig, Vuelta a Burgos stage 3 (22/5)
23: Lorena Wiebes, Ronde van Drenthe (23/10)
24: Alena Amialiusik, Lotto Belgium Tour stage 2 (24/6)
25: Anna Kiesenhofer, Olympic Games Road Race (25/7)
Kind of would have been easier to do a full month to move Vollering to the 26th for La Course and put VDBB in for Strade Bianche, which is a bigger and better win but it would be an egregious oversight to not include Vollering at all, or to omit Kiesenhofer. It also feels like a huge omission to not have van der Breggen for Flèche Wallonne, but Elisa's only other major victory this season falls outside of the dates involved, so I went for the Giro stage where she destroyed everybody in the mountains to end the GC battle on day 2. Similarly I wanted to put Reusser on for the European Championships which I thought was a bigger deal than the CDN, but Balsamo would have been otherwise omitted, and getting her first win in the rainbow stripes seemed a worthwhile enough inclusion.