Thermochromic　smart　windows　are　widely　developed　to　modulate　building　energy　exchange　to　save　building　energy　consumption.　However,　most　smart　windows　have　fixed　working　temperatures,　moderate　energy-saving　efficiency,　and　are　not　suitable　for　diverse　(cold　and　hot)　climates.　Here　smart　windows　with　strong　temperature　modulation　over　a　broad　range　of　hydrogels　with　adjustable　transition　temperatures　for　all-weather　building　temperature　regulation　in　different　climates　are　reported.　Thermochromic　poly(N-isopropylacrylamide-co-N,　N-dimethylacrylamide)　hydrogels,　with　lower　critical　transition　temperatures　ranging　from　32.5　to　43.5 °C,　are　developed　for　smart　windows　with　solar　modulation　up　to　88.84%　and　intrinsic　transmittance　up　to　91.30%　over　full　spectrum　without　energy　input.　Simulated　indoor　investigations　are　performed　in　different　cities　from　23　°N　to　39　°N　from　winter　to　summer.　The　results　indicate　that　smart　windows　have　a　strong　solar　modulation　in　summer　to　reduce　indoor　temperature　up　to　7.3 °C　and　efficient　heat　conservation　in　winter　to　save　energy　up　to　4.30 J m−3,　in　comparison　to　glass　windows.　Smart　windows　with　grid　patterns　and　Chinese　kirigami　are　fabricated　by　using　3D　printing　of　the　hydrogels　to　achieve　both　solar　modulation　and　light　incidence.　The　strategy　offers　an　innovative　path　for　thermochromic　smart　windows　for　low　carbon　economy.　©　2023　Wiley-VCH　GmbH.