June continued the streak this growing season for above normal temperatures and below normal rainfall across central and southeast Illinois. After a seasonable stretch of weather to start off the first couple weeks of June, a large ridge of high pressure in the mid levels of the atmosphere dominated the area for the last half of the month producing numerous hot and dry days. In fact, many areas saw their first triple digit highs on June 28 & 29 since early September 2011. Thunderstorm complexes primarily affected areas farther west and north in the Upper Midwest, while only sporadic and isolated events impacted the area. This led to a continued strengthening of the drought with large portions of central and southeast Illinois pushing into severe drought by late in the month. Extreme drought even crept into the southern parts of the state.
Maps below from the Midwestern Regional Climate Center highlight June temperature and precipitation anomalies across the area.
Preliminary climate summaries for specific cities in June 2012 are listed below. Lincoln reported their 3rd driest June on record (0.57"), and Springfield had their 5th driest June on record (0.94"). Only the summaries for Peoria, Springfield, and Lincoln are considered to be official climatological summaries. The remaining 4 sites are "supplemental", meaning a NWS Cooperative Observer in the area is the official climatological station for that location.