select pnm,lnm,st_cd,st_nm,cnty_id,dm,dm_date,dm_hist,avg_tmax_data,avg_tmin_data,avg_prcp_data,rec_hi_data,rec_lo_data,avg_sndp_data,x,y,ff,lf,fd,hz,er,hz_source,kg,hzd,clim_stn_nm,hz12,hz90, feels_like_min,feels_like_max,days_of_prcp,snow,cloud_cover,humidity,wind_speed from worldtg8_pm.pm_climate_points_namer where surl = 'big-rock' and st_surl='illinois' and iso_cc = 'US' and prim_loc in (1,2) Big Rock Illinois Climate Data - Updated February 2026

Big Rock Illinois Climate Data

Monthly Average Climate Data for Big Rock Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.1 °F29.9 °F1.87 in.
February17.2 °F34.0 °F1.84 in.
March27.1 °F46.2 °F2.33 in.
April37.7 °F59.3 °F3.73 in.
May49.2 °F70.7 °F4.78 in.
June59.1 °F80.4 °F4.42 in.
July62.9 °F83.6 °F3.78 in.
August60.8 °F81.6 °F3.82 in.
September52.7 °F75.8 °F3.32 in.
October40.9 °F62.9 °F3.28 in.
November30.2 °F48.1 °F2.5 in.
December20.1 °F35.3 °F2.13 in.
Annual39.3 °F59 °F37.8 in.

Climate Data for Big Rock Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 21 - Apr. 30
Average Days With Frost100-125 Days
Plant Hardiness ZoneZone 5b : -15°F to -10°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
2026 plantmaps.com