NowmalIllinois › Olney

Olney, Illinois

The week’s forecast, measured against two yardsticks: the “normal” your weather app still uses — a 1991–2020 average centered on 2005 — and the climate-adjusted normal, which here runs +0.4°F warmer. Same NOAA data. No pretending.

Year-round gap
+0.4°F
how far “normal” lags the climate here
Winter gap
+0.9°F
Dec–Feb normal high
Summer gap
+-0.6°F
Jun–Aug normal high
National rank
#2,639
of 3,136 U.S. counties
Traditional vs climate-adjusted normal through the year
Official 1991–2020 normal Climate-adjusted to 2026

Month by month

1991 called. It wants its climate baseline back.

MonthNormal highAdjusted high Normal lowAdjusted lowGap (high)
January38.4°38.6°22.6°23.5°+0.3°
February43.6°44.7°26.0°27.3°+1.1°
March54.1°55.6°34.8°36.4°+1.4°
April66.4°67.0°44.2°45.0°+0.7°
May75.7°75.7°54.9°56.4°+0.1°
June84.4°84.4°63.2°64.2°+0.0°
July87.2°86.3°66.7°67.8°+-0.9°
August86.1°85.3°64.5°65.3°+-0.7°
September80.4°80.5°56.9°57.7°+0.2°
October68.5°68.6°45.5°46.5°+0.1°
November54.0°54.8°35.2°36.2°+0.9°
December42.6°43.9°26.9°28.5°+1.3°
Why this number exists

The “normal” temperature in every weather app is a 30-year average (1991–2020) — a number centered on mid-2005, two decades out of date in a warming climate. The Climate-Adjusted Normal takes NOAA’s official normal and advances it to the present using this county’s own measured warming trend.

It isn’t a forecast — it’s a more honest yardstick for what “normal” means now. Read why Nowmal exists →

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About this data

The forecast is the National Weather Service’s, for Olney itself. Normals and the warming trend are computed at county level (Richland County) from NOAA’s homogenized climate record, because climate trends vary smoothly — nearby towns warm at statistically indistinguishable rates. Method details on the methodology page.

Richland County data page

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