Yn ystod 2021, cyrhaeddodd Her Ddarllen yr Haf 21,148 o blant ledled Cymru mewn partneriaeth â llyfrgelloedd cyhoeddus. Parhaodd yr Her i gyrraedd ymhell dros hanner miliwn o blant ledled y DU yn 2021 wrth i'r cyfyngiadau symud leddfu, gan gymell plant i barhau i ddarllen yn ystod cyfnod anodd. Dywedodd teuluoedd wrth yr Asiantaeth Ddarllen fod cymryd rhan yn Her Ddarllen yr Haf wedi helpu eu plant i fwynhau darllen mwy, teimlo'n fwy hyderus am ddarllen a 'theimlo'n well' yn ystod cyfnod anodd. Cynyddodd defnydd teuluol o lyfrgelloedd hefyd ymhlith cyfranogwyr yr Her, gyda mwy na 1779 o blant o Gymru yn ymuno â'r llyfrgell fel aelodau newydd.
During 2021, the Summer Reading Challenge reached 21,148 children across Wales in partnership with public libraries. The Challenge continued to reach well over half a million children across the UK in 2021 as lockdowns eased, motivating children to keep reading during a difficult time. Families told The Reading Agency that taking part in the Summer Reading Challenge helped their children to enjoy reading more, feel more confident about reading and ‘feel better’ during a tough period. Family use of libraries also increased amongst Challenge participants, with more than 1779 children from Wales joining the library as new members.