Brood VI (6) 17-year cicadas (“locusts”) will emerge in the spring of 2034. The main group will emerge in South Carolina, North Carolina and Georgia. Other lesser groups should emerge in Ohio & Wisconsin.
About Brood VI:
The cicada species that will emerge are Magicicada septendecim1, Magicicada septendecula1, and possibly Magicicada cassini2. These periodical cicadas have a 17-year life cycle. The last times they emerged was 2017 and 2000.
When: Generally speaking, these cicadas will begin to emerge when the soil 8" beneath the ground reaches 64 degrees Fahrenheit 3. A nice, warm rain will often trigger an emergence. So, definitely May, but something might happen in April if we have a particularly hot spring.
Report a sighting: If you see or heard cicadas, please report them to Cicadas @ UCONN (formerly Magicicada.org). This helps researchers map the location of the cicadas.
Locations where they are likely to emerge:
Georgia: Counties: Best bet: Rabun.6. 1889 document: Dade (Trenton), Elbert (Elberton), Floyd (Rome), Habersham (Turnerville), Hill (Virgil), Paulding (Brownsville), Rabun, Spalding (Experiment), White (Tesnatee). 7 Not Atlanta.
North Carolina: Counties: Best bet: Buncombe (Asheville), Burke, Caldwell, Henderson, McDowell, Polk, Wilkes6. 1889 document: Alexander (Mount Pisgah, Taylorsville), Bladen, Buncombe (Asheville), Burke (Morganton), Cabarrus, Caldwell (Lenoir, Hickory), Catawba (Claremont, Maiden), Henderson (Westfeldt Park, Horse Shoe), Iredell, Lincoln (Denver, Lincolnton), Macon (Franklin), McDowell (Greenlee), Moore, Montgomery, Pender (Long Creek), Polk (Columbus, Saluda, Mill Spring), Rabun (Highlands), Randolph, Rutherford, Swain (Whittier), Transylvania, Union (Waxhaw), Washington, Wilkes (Moravian Falls, Wilkesboro).7
South Carolina: Counties: Best bet: Oconee, Pickens6. 1889 document: Oconee (Stumphouse Mountain which is near Westminster).7

Ohio Counties: Best bet: Hamilton (Hyde Park, Delhi, Finneytown, Green Township, Anderson). 5. 1889 document: Carroll, Champaign, Columbiana, Delaware, Madison, Mahoning, Montgomery, Morrow, Pickaway, Shelby, Union.
Oklahoma As I understand it, there may be populations in eastern Oklahoma that might exist, but no one has checked yet (or documented it). Researchers hope to check this year.5
Learn more about Brood VI:
1907 Map Marlatt, C.L.. 1907. The periodical cicada. Washington, D.C. : U.S. Dept. of Agriculture, Bureau of Entomology.
For historical purposes only — it’s definitely not accurate. Compare to the map on Cicadas @ UCONN (formerly Magicicada.org).

What happened in 2017?
Wisconsin was a bust.
Final Update: I traveled to Wisconsin last week and spent a few days looking for cicadas in the southern part of the state (Madison, Baraboo, Janesville, Cedar Bluff, Dodgeville) but unfortunately I did not see or hear any. :(. So far this year though, Brood VI was spotted in GA, NC, SC, OK, OH and perhaps NY….

Previous updates can be found in the comments.
1 Teiji Sota, Satoshi Yamamoto, John R. Cooley, Kathy B.R. Hill, Chris Simon, and Jin Yoshimu. Independent divergence of 13- and 17-y life cycles among three lineages of periodical cicada lineages. Proceedings of the National Academy of Sciences of the USA.
2 Gene Kritsky Periodical Cicadas the Plague and the Puzzle (2004, Indiana Academy of Science, page 97)
3 James Edward Heath, Thermal Synchronization of Emergence in Periodical “17-year” Cicadas (Homoptera, Cicadidae, Magicicada) American Midland Naturalist, Vol. 80, No. 2. (Oct. 1968), pp. 440-448.
4 David C Marshall Periodical Cicada (Homoptera: Cicadidae) Life-Cycle Variations, the Historical Emergence Record, and the Geographic Stability of Brood Distributions. Ann. Entomol. Soc. Am. 94(3): 386Ã399 (2001). Link to website where you can get this document.
5 Information from John Cooley of Cicadas @ UCONN (formerly Magicicada.org), Gene Kritsky, & Roy Troutman, relayed by email.
6 Magicicada Database Query Page (RIP).
7 C.L. Marlatt, Thermal Synchronization of Emergence in Periodical “17-year” Cicadas (Homoptera, Cicadidae, Magicicada), United States. Bureau of Entomology, 1889b, (1889). Find this online in the document Some miscellaneous results of the work of the Division of Entomology, III (Archive.org) compiled by United State Division of Entomology in 1889.
* The map is based on this map from the Wikimedia Commons by Lokal_Profil. The data for the map come’s from Cicadas @ UCONN (formerly Magicicada.org).