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 = 'diamond' and st_surl='illinois' and iso_cc = 'US' and prim_loc in (1,2) Diamond Illinois Climate Data - Updated February 2026

Diamond Illinois Climate Data

Monthly Average Climate Data for Diamond Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January15.9 °F31.7 °F2.14 in.
February18.8 °F35.8 °F1.9 in.
March28.4 °F47.8 °F2.38 in.
April38.8 °F60.9 °F3.68 in.
May50.1 °F72.0 °F4.79 in.
June60.1 °F81.4 °F4.56 in.
July63.6 °F84.6 °F4.04 in.
August61.8 °F82.7 °F3.83 in.
September53.9 °F77.5 °F3.36 in.
October42.1 °F64.2 °F3.05 in.
November31.5 °F49.4 °F2.47 in.
December21.7 °F36.9 °F2.08 in.
Annual40.6 °F60.4 °F38.28 in.

Climate Data for Diamond Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 11 - Apr. 20
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
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