Illinois frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Baileyville | Apr 26 | Oct 13 | 170 d | 5a |
| Baldwin | Apr 12 | Oct 22 | 193 d | 7a |
| Bardolph | Apr 17 | Oct 22 | 188 d | 6a |
| Barnhill | Apr 7 | Oct 26 | 202 d | 6b |
| Barrington | Apr 25 | Oct 19 | 177 d | 5b |
| Barrington (Lake) | Apr 30 | Oct 19 | 172 d | 5b |
| Barry | Apr 18 | Oct 15 | 180 d | 6a |
| Barstow | Apr 16 | Oct 25 | 192 d | 5b |
| Bartelso | Apr 6 | Oct 29 | 206 d | 6b |
| Bartlett | Apr 30 | Oct 13 | 166 d | 5b |
| Basco | Apr 13 | Oct 22 | 192 d | 6a |
| Batavia | Apr 19 | Oct 23 | 187 d | 5b |
| Batchtown | Apr 20 | Oct 20 | 183 d | 6b |
| Bath | Apr 17 | Oct 19 | 185 d | 6a |
| Baylis | Apr 18 | Oct 15 | 180 d | 6a |
| Beardstown | Apr 16 | Oct 23 | 190 d | 6a |
| Beason | Apr 20 | Oct 16 | 179 d | 6a |
| Beaverville | Apr 24 | Oct 16 | 175 d | 5b |
| Beckemeyer | Apr 6 | Oct 29 | 206 d | 6b |
| Bedford Park | Apr 11 | Oct 31 | 203 d | 6a |
| Beecher | Apr 23 | Oct 20 | 180 d | 6a |
| Beecher City | Apr 13 | Oct 24 | 194 d | 6b |
| Belknap | Apr 3 | Nov 5 | 216 d | 7a |
| Belle Rive | Apr 11 | Oct 22 | 194 d | 6b |
| Belleville | Apr 12 | Oct 20 | 191 d | 7a |
| Bellflower | Apr 21 | Oct 17 | 179 d | 6a |
| Bellmont | Apr 4 | Oct 28 | 207 d | 6b |
| Bellwood | Apr 16 | Oct 28 | 195 d | 6a |
| Belvidere | Apr 28 | Oct 12 | 167 d | 5b |
| Bement | Apr 23 | Oct 13 | 173 d | 6a |
| Benld | Apr 14 | Oct 21 | 190 d | 6b |
| Bensenville | Apr 16 | Oct 28 | 195 d | 6a |
| Benson | Apr 26 | Oct 17 | 174 d | 5b |
| Benton | Apr 4 | Oct 28 | 207 d | 7a |
| Berkeley | Apr 16 | Oct 28 | 195 d | 6a |
| Berwick | Apr 22 | Oct 19 | 180 d | 5b |
| Berwyn | Apr 11 | Oct 31 | 203 d | 6a |
| Bethalto | Apr 4 | Nov 5 | 215 d | 6b |
| Bethany | Apr 15 | Oct 22 | 190 d | 6a |
| Big Rock | Apr 28 | Oct 13 | 168 d | 5b |
| Biggsville | Apr 8 | Oct 29 | 204 d | 5b |
| Bingham | Apr 15 | Oct 19 | 187 d | 6b |
| Bishop Hill | Apr 26 | Oct 12 | 169 d | 5b |
| Bismarck | Apr 21 | Oct 20 | 182 d | 6a |
| Blackstone | Apr 12 | Oct 28 | 199 d | 5b |
| Blandinsville | Apr 21 | Oct 19 | 181 d | 6a |
| Bloomingdale | Apr 28 | Oct 16 | 171 d | 5b |
| Bloomington | Apr 25 | Oct 16 | 174 d | 6a |
| Blue Island | Apr 10 | Nov 1 | 205 d | 6a |
| Blue Mound | Apr 14 | Oct 24 | 193 d | 6a |
| Bluff Springs | Apr 16 | Oct 23 | 190 d | 6a |
| Bluffs | Apr 18 | Oct 20 | 185 d | 6a |
| Bluford | Apr 11 | Oct 22 | 194 d | 6b |
| Boles | Apr 14 | Oct 21 | 190 d | 7a |
| Bolingbrook | Apr 20 | Oct 22 | 185 d | 6a |
| Bondville | Apr 23 | Oct 13 | 173 d | 6a |
| Bone Gap | Apr 4 | Oct 28 | 207 d | 6b |
| Bonfield | Apr 19 | Oct 24 | 188 d | 5b |
| Bonnie | Apr 11 | Oct 22 | 194 d | 6b |
| Boody | Apr 14 | Oct 24 | 193 d | 6a |
| Bourbonnais | Apr 19 | Oct 24 | 188 d | 5b |
| Bowen | Apr 13 | Oct 22 | 192 d | 6a |
| Braceville | Apr 27 | Oct 15 | 171 d | 5b |
| Bradford | Apr 24 | Oct 17 | 176 d | 5b |
| Bradley | Apr 19 | Oct 24 | 188 d | 5b |
| Braidwood | Apr 16 | Oct 26 | 193 d | 5b |
| Breese | Apr 6 | Oct 29 | 206 d | 6b |
| Bridgeport | Apr 12 | Oct 25 | 196 d | 6b |
| Bridgeview | Apr 10 | Nov 1 | 205 d | 6a |
| Brighton | Apr 14 | Oct 19 | 188 d | 6b |
| Brimfield | Apr 22 | Oct 14 | 175 d | 5b |
| Bristol | Apr 28 | Oct 13 | 168 d | 5b |
| Broadlands | Apr 19 | Oct 19 | 183 d | 6a |
| Broadview | Apr 11 | Oct 31 | 203 d | 6a |
| Brocton | Apr 21 | Oct 20 | 182 d | 6a |
| Brookfield | Apr 11 | Oct 31 | 203 d | 6a |
| Brookport | Apr 3 | Oct 30 | 210 d | 7a |
| Broughton | Apr 11 | Oct 21 | 193 d | 7a |
| Browning | Apr 16 | Oct 23 | 190 d | 6a |
| Browns | Apr 4 | Oct 28 | 207 d | 6b |
| Brownstown | Apr 3 | Oct 24 | 204 d | 6b |
| Brussels | Apr 5 | Oct 27 | 205 d | 6b |
| Bryant | Apr 17 | Oct 19 | 185 d | 6a |
| Buckingham | Apr 27 | Oct 15 | 171 d | 5b |
| Buckley | Apr 23 | Oct 12 | 172 d | 6a |
| Buckner | Apr 4 | Oct 27 | 206 d | 7a |
| Buda | Apr 22 | Oct 17 | 178 d | 5b |
| Buffalo | Apr 14 | Oct 20 | 189 d | 6a |
| Buffalo Grove | Apr 19 | Oct 26 | 190 d | 6a |
| Buffalo Prairie | Apr 18 | Oct 24 | 189 d | 5b |
| Bulpitt | Apr 12 | Oct 20 | 191 d | 6a |
| Buncombe | Apr 8 | Oct 29 | 204 d | 7a |
| Bunker Hill | Apr 4 | Nov 5 | 215 d | 6b |
| Burbank | Apr 10 | Nov 1 | 205 d | 6a |
| Bureau | Apr 24 | Oct 17 | 176 d | 5b |
| Burlington | Apr 26 | Oct 18 | 175 d | 5b |
| Burnt Prairie | Apr 15 | Oct 19 | 187 d | 6b |
| Bushnell | Apr 17 | Oct 22 | 188 d | 6a |
| Butler | Apr 13 | Oct 24 | 194 d | 6b |
| Byron | Apr 24 | Oct 17 | 176 d | 5b |