Point Forecast: Ashton-Sandy Spring MD  39.15N 77.01W (Elev. 137 m)	Last Update: 2:22 am EDT May 20, 2026

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Weather Elements Fire Weather Aviation Weather 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 Vent Rate (x1000 mph-m) Atmospheric Dispersion Index Low Visibility Occurrence Risk Index Ceiling Height Visibility

48-Hour Period Starting: 2am Wed, May 20 20263am Wed, May 20 20264am Wed, May 20 20265am Wed, May 20 20266am Wed, May 20 20267am Wed, May 20 20268am Wed, May 20 20269am Wed, May 20 202610am Wed, May 20 202611am Wed, May 20 202612pm Wed, May 20 20261pm Wed, May 20 20262pm Wed, May 20 20263pm Wed, May 20 20264pm Wed, May 20 20265pm Wed, May 20 20266pm Wed, May 20 20267pm Wed, May 20 20268pm Wed, May 20 20269pm Wed, May 20 202610pm Wed, May 20 202611pm Wed, May 20 202612am Thu, May 21 20261am Thu, May 21 20262am Thu, May 21 20263am Thu, May 21 20264am Thu, May 21 20265am Thu, May 21 20266am Thu, May 21 20267am Thu, May 21 20268am Thu, May 21 20269am Thu, May 21 202610am Thu, May 21 202611am Thu, May 21 202612pm Thu, May 21 20261pm Thu, May 21 20262pm Thu, May 21 20263pm Thu, May 21 20264pm Thu, May 21 20265pm Thu, May 21 20266pm Thu, May 21 20267pm Thu, May 21 20268pm Thu, May 21 20269pm Thu, May 21 202610pm Thu, May 21 202611pm Thu, May 21 202612am Fri, May 22 20261am Fri, May 22 20262am Fri, May 22 20263am Fri, May 22 20264am Fri, May 22 20265am Fri, May 22 20266am Fri, May 22 20267am Fri, May 22 20268am Fri, May 22 20269am Fri, May 22 202610am Fri, May 22 202611am Fri, May 22 202612pm Fri, May 22 20261pm Fri, May 22 20262pm Fri, May 22 20263pm Fri, May 22 20264pm Fri, May 22 20265pm Fri, May 22 20266pm Fri, May 22 20267pm Fri, May 22 20268pm Fri, May 22 20269pm Fri, May 22 202610pm Fri, May 22 202611pm Fri, May 22 202612am Sat, May 23 20261am Sat, May 23 20262am Sat, May 23 20263am Sat, May 23 20264am Sat, May 23 20265am Sat, May 23 20266am Sat, May 23 20267am Sat, May 23 20268am Sat, May 23 20269am Sat, May 23 202610am Sat, May 23 202611am Sat, May 23 202612pm Sat, May 23 20261pm Sat, May 23 20262pm Sat, May 23 20263pm Sat, May 23 20264pm Sat, May 23 20265pm Sat, May 23 20266pm Sat, May 23 20267pm Sat, May 23 20268pm Sat, May 23 20269pm Sat, May 23 202610pm Sat, May 23 202611pm Sat, May 23 202612am Sun, May 24 20261am Sun, May 24 20262am Sun, May 24 20263am Sun, May 24 20264am Sun, May 24 20265am Sun, May 24 20266am Sun, May 24 20267am Sun, May 24 20268am Sun, May 24 20269am Sun, May 24 202610am Sun, May 24 202611am Sun, May 24 202612pm Sun, May 24 20261pm Sun, May 24 2026

Date	05/20																						05/21
Hour (EDT)	02	03	04	05	06	07	08	09	10	11	12	13	14	15	16	17	18	19	20	21	22	23	00	01
Temperature (°C)	23	23	22	22	22	23	25	27	28	31	31	32	33	32	31	30	27	26	24	23	22	22	21	20
Dewpoint (°C)	18	18	18	18	18	18	18	18	19	19	19	19	19	19	19	20	21	22	22	21	21	19	18	18
Heat Index (°C)							25	28	30	32	32	33	34	34	32	32	29	26	24
Surface Wind (mph)	5	5	3	3	3	3	2	3	5	6	6	6	7	7	8	8	7	7	6	5	5	3	5	5
Wind Dir	SW	SW	SW	SW	W	W	W	W	W	W	W	W	W	W	W	W	NW	NW	N	N	N	N	N	N
Gust
Sky Cover (%)	39	35	19	18	22	18	12	9	10	14	16	22	45	58	76	83	85	85	86	84	85	89	90	92
Precipitation Potential (%)	5	5	5	4	5	7	6	5	7	9	9	6	17	35	63	67	62	46	62	59	63	50	45	49
Relative Humidity (%)	76	73	76	76	79	73	64	60	59	52	48	47	44	45	48	55	67	77	87	90	93	87	87	87
Rain	--	--	--	--	--	--	--	--	--	--	--	--	SChc	Chc	Lkly	Lkly	Lkly	Chc	Lkly	Lkly	Lkly	Chc	Chc	Chc
Thunder	--	--	--	--	--	--	--	--	--	--	--	--	SChc	Chc	Chc	Chc	Chc	Chc	Chc	Chc	Chc	SChc	SChc	SChc
Date																							05/22
Hour (EDT)	02	03	04	05	06	07	08	09	10	11	12	13	14	15	16	17	18	19	20	21	22	23	00	01
Temperature (°C)	19	18	16	16	16	14	15	15	16	16	16	16	17	17	17	17	16	16	16	15	14	14	14	14
Dewpoint (°C)	17	15	14	13	12	11	11	11	13	12	12	13	13	13	13	13	13	13	13	13	13	13	13	13
Heat Index (°C)
Surface Wind (mph)	5	6	7	7	8	8	8	8	8	8	8	7	7	7	7	7	6	5	3	2	2	2	2	2
Wind Dir	N	N	N	N	NE	NE	NE	N	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE	NE
Gust
Sky Cover (%)	93	91	90	90	90	90	92	91	94	95	94	94	92	92	92	92	90	87	86	80	79	83	83	83
Precipitation Potential (%)	43	43	43	40	40	40	67	74	74	60	69	75	71	65	58	48	43	26	40	40	40	40	40	40
Relative Humidity (%)	87	81	87	81	81	83	78	78	81	78	78	81	75	78	78	78	81	81	84	90	93	90	93	93
Rain	Chc	Chc	Chc	Chc	Chc	Chc	Lkly	Lkly	Lkly	Lkly	Lkly	Ocnl	Lkly	Lkly	Lkly	Chc	Chc	Chc	Chc	Chc	Chc	Chc	Chc	Chc
Thunder	--	--	--	--	--	--	SChc	SChc	SChc	SChc	SChc	SChc	SChc	SChc	SChc	--	--	--	--	--	--	--	--	--

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