Point Forecast: Chicago/Romeoville, Lewis University Airport IL  41.61N 88.1W	Last Update: 7:01 pm CDT Aug 18, 2026

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Weather Elements Fire Weather Probabilistic Forecasts (Experimental) Description | Survey Temperature (°C) Dewpoint (°C) Heat Index (°C) Surface Wind  ktmphkm/hm/s Sky Cover (%) Precipitation Potential (%) Relative Humidity (%) Rain Thunder Fog Mixing Height  x100ftx100m Trans. Wind  ktmphkm/hm/s 20ft Wind  ktmphkm/hm/s Vent Rate (x1000 mph-m) Quantitative Precipitation  3-hr6-hr12-hr24-hr   info     0.100.250.501.00 Snowfall  3-hr6-hr12-hr24-hr   info     0.1in1in3in6in12in

48-Hour Period Starting: 9pm Tue, Aug 18 202610pm Tue, Aug 18 202611pm Tue, Aug 18 202612am Wed, Aug 19 20261am Wed, Aug 19 20262am Wed, Aug 19 20263am Wed, Aug 19 20264am Wed, Aug 19 20265am Wed, Aug 19 20266am Wed, Aug 19 20267am Wed, Aug 19 20268am Wed, Aug 19 20269am Wed, Aug 19 202610am Wed, Aug 19 202611am Wed, Aug 19 202612pm Wed, Aug 19 20261pm Wed, Aug 19 20262pm Wed, Aug 19 20263pm Wed, Aug 19 20264pm Wed, Aug 19 20265pm Wed, Aug 19 20266pm Wed, Aug 19 20267pm Wed, Aug 19 20268pm Wed, Aug 19 20269pm Wed, Aug 19 202610pm Wed, Aug 19 202611pm Wed, Aug 19 202612am Thu, Aug 20 20261am Thu, Aug 20 20262am Thu, Aug 20 20263am Thu, Aug 20 20264am Thu, Aug 20 20265am Thu, Aug 20 20266am Thu, Aug 20 20267am Thu, Aug 20 20268am Thu, Aug 20 20269am Thu, Aug 20 202610am Thu, Aug 20 202611am Thu, Aug 20 202612pm Thu, Aug 20 20261pm Thu, Aug 20 20262pm Thu, Aug 20 20263pm Thu, Aug 20 20264pm Thu, Aug 20 20265pm Thu, Aug 20 20266pm Thu, Aug 20 20267pm Thu, Aug 20 20268pm Thu, Aug 20 20269pm Thu, Aug 20 202610pm Thu, Aug 20 202611pm Thu, Aug 20 202612am Fri, Aug 21 20261am Fri, Aug 21 20262am Fri, Aug 21 20263am Fri, Aug 21 20264am Fri, Aug 21 20265am Fri, Aug 21 20266am Fri, Aug 21 20267am Fri, Aug 21 20268am Fri, Aug 21 20269am Fri, Aug 21 202610am Fri, Aug 21 202611am Fri, Aug 21 202612pm Fri, Aug 21 20261pm Fri, Aug 21 20262pm Fri, Aug 21 20263pm Fri, Aug 21 20264pm Fri, Aug 21 20265pm Fri, Aug 21 20266pm Fri, Aug 21 20267pm Fri, Aug 21 20268pm Fri, Aug 21 20269pm Fri, Aug 21 202610pm Fri, Aug 21 202611pm Fri, Aug 21 202612am Sat, Aug 22 20261am Sat, Aug 22 20262am Sat, Aug 22 20263am Sat, Aug 22 20264am Sat, Aug 22 20265am Sat, Aug 22 20266am Sat, Aug 22 20267am Sat, Aug 22 20268am Sat, Aug 22 20269am Sat, Aug 22 202610am Sat, Aug 22 202611am Sat, Aug 22 202612pm Sat, Aug 22 20261pm Sat, Aug 22 20262pm Sat, Aug 22 20263pm Sat, Aug 22 20264pm Sat, Aug 22 20265pm Sat, Aug 22 20266pm Sat, Aug 22 20267pm Sat, Aug 22 20268pm Sat, Aug 22 20269pm Sat, Aug 22 202610pm Sat, Aug 22 202611pm Sat, Aug 22 202612am Sun, Aug 23 20261am Sun, Aug 23 20262am Sun, Aug 23 20263am Sun, Aug 23 20264am Sun, Aug 23 20265am Sun, Aug 23 20266am Sun, Aug 23 20267am Sun, Aug 23 20268am Sun, Aug 23 2026

Date	08/18			08/19
Hour (CDT)	21	22	23	00	01	02	03	04	05	06	07	08	09	10	11	12	13	14	15	16	17	18	19	20
Temperature (°C)	22	22	21	21	20	20	19	19	19	18	19	20	21	22	23	24	26	26	26	26	25	24	23	22
Dewpoint (°C)	21	21	21	19	19	19	19	19	18	18	19	19	20	20	20	20	20	20	19	19	19	19	18	17
Heat Index (°C)																24	26	26	27	26	25	24
Surface Wind (mph)	6	6	6	6	6	5	5	3	3	3	3	3	3	3	3	5	5	5	6	6	6	6	6	6
Wind Dir	SSW	SW	SW	SW	WSW	WSW	W	W	WNW	W	WNW	NNW	N	NNE	NE	NE	NNW	NNW	NNW	N	N	NE	E	E
Gust
Sky Cover (%)	77	80	73	73	70	76	76	68	66	66	64	65	67	68	72	74	76	69	63	58	54	53	55	64
Precipitation Potential (%)	54	70	65	57	43	26	20	14	13	11	7	2	6	9	8	8	9	7	9	18	18	18	5	3
Relative Humidity (%)	90	94	96	95	95	97	98	98	99	100	100	98	94	88	82	76	72	69	67	67	69	72	75	77
Rain	Chc	Lkly	Lkly	Lkly	Chc	Chc	SChc	--	--	--	--	--	--	--	--	--	--	--	--	SChc	SChc	SChc	--	--
Thunder	Chc	Lkly	Lkly	Chc	Chc	Chc	SChc	--	--	--	--	--	--	--	--	--	--	--	--	SChc	SChc	SChc	--	--
Date				08/20
Hour (CDT)	21	22	23	00	01	02	03	04	05	06	07	08	09	10	11	12	13	14	15	16	17	18	19	20
Temperature (°C)	21	19	19	18	18	17	17	17	16	16	16	18	21	23	24	26	26	26	26	26	26	25	24	23
Dewpoint (°C)	17	17	17	17	16	16	16	15	15	15	16	17	17	17	17	17	17	17	17	17	17	17	17	17
Heat Index (°C)															24	26	26	26	27	26	26	25	24
Surface Wind (mph)	5	3	2	1	2	1	1	1	1	1	1	1	2	2	2	3	3	3	3	3	3	3	2	2
Wind Dir	E	E	E	ENE	NE	NE	NNE	NNE	NNE	NNE	N	NNE	NE	NE	ENE	E	E	ESE	SE	SSE	SSE	SE	SE	SE
Gust
Sky Cover (%)	63	64	48	48	57	43	32	31	27	28	42	50	30	10	9	9	8	10	13	15	15	15	15	17
Precipitation Potential (%)	2	1	0	1	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Relative Humidity (%)	81	85	89	90	90	90	90	91	93	94	95	92	82	71	64	60	57	56	56	56	58	61	66	71
Rain	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--
Thunder	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--	--

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