Newport News Municipal Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Newport News Municipal Park clear sky chart from 2005-11-06 to 2026-05-02.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	12% 6% 2 6% 4 4 5% 4 6% 8% 43%	131537
	Night	13% 6% 2 6% 4 4 4 3 5% 7% 44%	130955
Transparency	Day	24% 38% 9% 14% 12% 3	135129
	Night	25% 37% 7% 15% 12% 3	135433
Seeing	Day	16% 12% 29% 25% 14% 4	17129
	Night	17% 10% 29% 30% 13% 2	26818

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 4 1 5% 3 3 3 2 4 5% 55%	4961
	11th to 20th	Day	13% 6% 2 5% 3 2 2 3 4 5% 55%	5280
	21st to end	Day	12% 7% 3 7% 5% 4 4 4 4 5% 45%	5780
February	1st to 10th	Day	12% 8% 3 6% 4 5% 4 4 6% 6% 41%	1890
	11th to 20th	Day	22% 6% 2 4 3 3 3 3 4 6% 44%	1988
	21st to end	Day	16% 8% 3 5% 4 4 5% 4 7% 6% 38%	1730
March	1st to 10th	Day	18% 8% 3 6% 4 3 4 3 4 7% 40%	4902
	11th to 20th	Day	10% 6% 3 5% 4 3 3 3 4 7% 51%	5090
	21st to end	Day	14% 6% 2 5% 4 4 4 3 5% 7% 46%	5740
April	1st to 10th	Day	12% 5% 2 5% 4 4 4 2 5% 6% 51%	2520
	11th to 20th	Day	9% 5% 2 5% 4 4 4 4 6% 7% 48%	2494
	21st to end	Day	13% 7% 2 6% 4 4 4 4 6% 7% 45%	2520
May	1st to 10th	Day	12% 8% 2 7% 5% 5% 5% 4 7% 10% 35%	5458
	11th to 20th	Day	17% 7% 3 7% 5% 4 5% 4 6% 9% 32%	6077
	21st to end	Day	14% 5% 2 5% 3 4 4 4 6% 9% 43%	6934
June	1st to 10th	Day	10% 5% 2 5% 4 5% 5% 5% 6% 10% 43%	2800
	11th to 20th	Day	10% 6% 2 5% 4 5% 5% 4 7% 10% 42%	2800
	21st to end	Day	6% 4 2 5% 5% 6% 6% 5% 7% 12% 42%	2800
July	1st to 10th	Day	7% 4 2 6% 5% 5% 7% 5% 8% 12% 39%	6360
	11th to 20th	Day	10% 7% 3 8% 6% 6% 6% 5% 8% 12% 28%	6004
	21st to end	Day	6% 5% 2 7% 5% 5% 6% 6% 9% 12% 36%	6424
August	1st to 10th	Day	14% 8% 3 8% 5% 6% 6% 5% 7% 10% 27%	4234
	11th to 20th	Day	10% 6% 2 8% 5% 6% 6% 5% 7% 9% 35%	3851
	21st to end	Day	8% 5% 2 5% 4 4 5% 4 7% 12% 46%	4312
September	1st to 10th	Day	14% 5% 2 5% 4 4 5% 4 6% 9% 42%	2400
	11th to 20th	Day	15% 6% 3 6% 5% 5% 5% 4 6% 6% 41%	2400
	21st to end	Day	20% 8% 3 6% 4 4 4 3 6% 6% 36%	2132
October	1st to 10th	Day	15% 6% 2 5% 5% 3 4 3 5% 6% 46%	2000
	11th to 20th	Day	14% 7% 2 5% 3 3 3 3 4 5% 52%	2000
	21st to end	Day	12% 4 3 6% 4 3 3 3 4 6% 53%	2200
November	1st to 10th	Day	13% 5% 2 5% 4 3 4 2 4 7% 51%	1967
	11th to 20th	Day	13% 6% 2 4 3 2 3 2 5% 7% 51%	1890
	21st to end	Day	14% 4 2 4 3 3 3 3 5% 6% 51%	1801
December	1st to 10th	Day	11% 5% 2 5% 3 3 3 3 5% 6% 54%	2680
	11th to 20th	Day	15% 8% 3 5% 4 3 3 3 4 5% 47%	3070
	21st to end	Day	12% 5% 2 6% 3 3 4 3 5% 7% 49%	4048
January	1st to 10th	Night	11% 6% 2 6% 4 4 4 3 5% 6% 50%	7915
	11th to 20th	Night	12% 6% 2 6% 3 3 3 3 4 4 54%	7680
	21st to end	Night	16% 6% 2 6% 3 3 3 2 4 6% 48%	8401
February	1st to 10th	Night	17% 7% 2 6% 4 3 4 3 5% 6% 43%	2730
	11th to 20th	Night	21% 7% 2 6% 4 3 3 3 5% 5% 41%	2516
	21st to end	Night	16% 7% 2 6% 4 3 3 3 4 6% 46%	2076
March	1st to 10th	Night	18% 7% 2 6% 4 3 3 3 4 5% 44%	5168
	11th to 20th	Night	13% 6% 3 6% 4 4 3 3 4 6% 49%	5090
	21st to end	Night	13% 6% 2 6% 4 4 4 3 5% 5% 47%	5432
April	1st to 10th	Night	13% 6% 3 6% 4 4 4 3 6% 7% 43%	2100
	11th to 20th	Night	12% 5% 2 4 4 4 3 3 5% 7% 50%	2075
	21st to end	Night	13% 6% 2 5% 4 4 5% 3 5% 7% 46%	2100
May	1st to 10th	Night	13% 8% 3 9% 6% 5% 5% 4 6% 8% 32%	4501
	11th to 20th	Night	20% 8% 3 7% 5% 4 4 4 6% 7% 33%	3814
	21st to end	Night	15% 7% 2 6% 5% 4 4 3 5% 8% 39%	3920
June	1st to 10th	Night	12% 5% 1 6% 5% 5% 5% 4 7% 10% 40%	1600
	11th to 20th	Night	10% 6% 2 6% 5% 4 6% 5% 7% 9% 41%	1600
	21st to end	Night	8% 5% 2 6% 6% 5% 5% 5% 7% 8% 44%	1600
July	1st to 10th	Night	9% 4 3 6% 5% 6% 6% 5% 8% 11% 37%	3598
	11th to 20th	Night	10% 7% 3 8% 4 5% 7% 6% 8% 11% 29%	3935
	21st to end	Night	10% 7% 3 8% 5% 5% 6% 4 7% 10% 35%	4427
August	1st to 10th	Night	17% 8% 4 7% 4 5% 5% 5% 7% 9% 29%	2915
	11th to 20th	Night	9% 6% 3 8% 5% 5% 5% 4 7% 9% 39%	3162
	21st to end	Night	8% 5% 2 5% 4 4 4 3 7% 11% 45%	3586
September	1st to 10th	Night	12% 4 2 5% 5% 3 5% 4 7% 9% 45%	2000
	11th to 20th	Night	13% 7% 2 6% 4 5% 4 4 5% 7% 44%	2000
	21st to end	Night	20% 7% 3 8% 4 4 5% 3 5% 5% 36%	2263
October	1st to 10th	Night	14% 6% 2 5% 4 4 4 3 4 6% 48%	2400
	11th to 20th	Night	16% 6% 2 5% 3 3 3 3 4 6% 50%	2400
	21st to end	Night	14% 5% 1 4 3 4 3 3 5% 5% 52%	2640
November	1st to 10th	Night	14% 6% 2 5% 3 3 3 2 4 5% 50%	2550
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 5% 6% 48%	2730
	21st to end	Night	12% 4 2 5% 4 3 4 3 6% 6% 51%	2816
December	1st to 10th	Night	11% 5% 2 5% 3 4 4 3 4 6% 54%	4720
	11th to 20th	Night	17% 8% 3 7% 5% 4 4 3 5% 6% 40%	5345
	21st to end	Night	12% 6% 2 6% 4 3 4 3 5% 7% 48%	7150

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	25% 21% 9% 20% 16% 9%	4962
	11th to 20th	Day	24% 21% 3 14% 29% 9%	5280
	21st to end	Day	34% 23% 6% 22% 14% 2	5780
February	1st to 10th	Day	17% 60% 5% 10% 6% 1	1890
	11th to 20th	Day	20% 59% 4 8% 7% 3	1997
	21st to end	Day	19% 59% 5% 8% 7% 2	1730
March	1st to 10th	Day	36% 30% 5% 10% 13% 5%	4902
	11th to 20th	Day	22% 29% 7% 15% 20% 7%	5090
	21st to end	Day	26% 30% 10% 13% 16% 5%	5740
April	1st to 10th	Day	15% 60% 5% 10% 9% 1	2520
	11th to 20th	Day	14% 60% 6% 12% 7% 1	2494
	21st to end	Day	16% 59% 7% 10% 6% 2	2520
May	1st to 10th	Day	33% 34% 13% 13% 7% 1	5490
	11th to 20th	Day	35% 32% 12% 14% 6%	6081
	21st to end	Day	26% 32% 11% 18% 12% 2	6949
June	1st to 10th	Day	14% 64% 6% 9% 7% 1	2800
	11th to 20th	Day	12% 63% 7% 10% 7%	2800
	21st to end	Day	11% 62% 6% 13% 7%	2800
July	1st to 10th	Day	26% 31% 17% 15% 8% 2	6290
	11th to 20th	Day	37% 32% 19% 10% 2	5932
	21st to end	Day	28% 31% 11% 18% 13% 1	6240
August	1st to 10th	Day	36% 39% 11% 12% 2	4221
	11th to 20th	Day	25% 41% 9% 17% 7%	3887
	21st to end	Day	16% 38% 11% 21% 14% 1	4312
September	1st to 10th	Day	16% 60% 8% 9% 5% 2	2400
	11th to 20th	Day	20% 58% 5% 8% 7% 2	2400
	21st to end	Day	24% 58% 4 10% 3	2132
October	1st to 10th	Day	18% 38% 7% 16% 18% 2	3260
	11th to 20th	Day	12% 35% 3 12% 30% 7%	3240
	21st to end	Day	9% 35% 6% 20% 18% 11%	3538
November	1st to 10th	Day	18% 53% 4 14% 8% 2	1967
	11th to 20th	Day	16% 55% 5% 9% 12% 3	1890
	21st to end	Day	16% 54% 4 13% 11% 2	1801
December	1st to 10th	Day	21% 36% 4 20% 14% 4	2680
	11th to 20th	Day	30% 31% 10% 13% 13% 4	3066
	21st to end	Day	25% 27% 11% 23% 13% 1	4048
January	1st to 10th	Night	28% 21% 9% 17% 18% 7%	7916
	11th to 20th	Night	26% 21% 2 17% 26% 7%	7680
	21st to end	Night	31% 23% 5% 21% 16% 4	8401
February	1st to 10th	Night	17% 59% 6% 10% 6% 1	2730
	11th to 20th	Night	21% 58% 3 9% 7% 2	2518
	21st to end	Night	17% 59% 3 11% 7% 4	2076
March	1st to 10th	Night	32% 31% 5% 12% 13% 7%	5168
	11th to 20th	Night	25% 29% 6% 13% 18% 9%	5090
	21st to end	Night	28% 29% 6% 18% 13% 5%	5432
April	1st to 10th	Night	16% 61% 5% 8% 9% 1	2100
	11th to 20th	Night	14% 60% 5% 11% 7% 1	2075
	21st to end	Night	17% 60% 6% 10% 7% 1	2100
May	1st to 10th	Night	35% 34% 11% 12% 7%	4531
	11th to 20th	Night	37% 32% 9% 16% 4	3815
	21st to end	Night	31% 32% 10% 17% 8%	3927
June	1st to 10th	Night	17% 64% 6% 7% 6% 1	1600
	11th to 20th	Night	12% 64% 8% 9% 7%	1600
	21st to end	Night	12% 63% 5% 12% 8% 1	1600
July	1st to 10th	Night	30% 33% 13% 15% 8% 1	3560
	11th to 20th	Night	37% 34% 16% 11% 1	3887
	21st to end	Night	33% 30% 9% 16% 12%	4297
August	1st to 10th	Night	37% 38% 11% 12% 2	2904
	11th to 20th	Night	24% 40% 12% 16% 8%	3192
	21st to end	Night	19% 37% 6% 18% 19% 1	3586
September	1st to 10th	Night	15% 60% 10% 9% 4 1	2000
	11th to 20th	Night	19% 58% 5% 9% 8% 1	2000
	21st to end	Night	26% 58% 5% 8% 3	2263
October	1st to 10th	Night	23% 37% 8% 15% 16% 2	3920
	11th to 20th	Night	13% 36% 4 14% 25% 9%	3899
	21st to end	Night	9% 35% 4 23% 18% 10%	4252
November	1st to 10th	Night	20% 53% 4 11% 10% 2	2550
	11th to 20th	Night	17% 54% 3 9% 10% 6%	2730
	21st to end	Night	15% 54% 4 12% 12% 2	2816
December	1st to 10th	Night	20% 35% 4 20% 17% 4	4720
	11th to 20th	Night	34% 32% 7% 12% 10% 5%	5348
	21st to end	Night	27% 28% 11% 22% 12% 1	7150

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	24% 21% 39% 12% 4	275
	11th to 20th	Day	23% 25% 37% 12% 3	330
	21st to end	Day	16% 26% 40% 15% 2	363
February	1st to 10th	Day	18% 23% 40% 16% 3	330
	11th to 20th	Day	28% 25% 33% 12% 1	476
	21st to end	Day	22% 21% 37% 17% 3	446
March	1st to 10th	Day	18% 21% 39% 17% 5%	540
	11th to 20th	Day	22% 19% 36% 18% 4 1	540
	21st to end	Day	19% 19% 40% 16% 5% 1	594
April	1st to 10th	Day	17% 20% 39% 16% 6% 1	540
	11th to 20th	Day	12% 16% 39% 24% 7% 3	532
	21st to end	Day	16% 14% 35% 26% 8% 1	540
May	1st to 10th	Day	13% 17% 38% 21% 10% 2	507
	11th to 20th	Day	20% 9% 31% 25% 13% 2	527
	21st to end	Day	20% 6% 24% 27% 19% 5%	573
June	1st to 10th	Day	11% 4 26% 32% 22% 4	530
	11th to 20th	Day	13% 6% 21% 32% 22% 5%	530
	21st to end	Day	8% 4 17% 44% 23% 5%	530
July	1st to 10th	Day	9% 3 13% 40% 29% 7%	525
	11th to 20th	Day	8% 2 13% 36% 31% 9%	524
	21st to end	Day	8% 2 20% 35% 28% 8%	576
August	1st to 10th	Day	15% 3 20% 33% 22% 7%	526
	11th to 20th	Day	13% 3 17% 32% 25% 9%	519
	21st to end	Day	8% 4 19% 31% 26% 11%	583
September	1st to 10th	Day	16% 2 23% 26% 20% 13%	530
	11th to 20th	Day	16% 5% 21% 28% 20% 10%	530
	21st to end	Day	27% 8% 22% 25% 14% 4	530
October	1st to 10th	Day	18% 5% 23% 27% 19% 8%	530
	11th to 20th	Day	15% 14% 26% 27% 15% 3	530
	21st to end	Day	14% 13% 33% 25% 11% 5%	583
November	1st to 10th	Day	16% 9% 31% 26% 13% 4	487
	11th to 20th	Day	18% 17% 32% 23% 9%	430
	21st to end	Day	19% 17% 30% 22% 11% 2	341
December	1st to 10th	Day	21% 15% 42% 17% 4 1	220
	11th to 20th	Day	20% 14% 39% 20% 7%	220
	21st to end	Day	21% 19% 34% 18% 8%	242
January	1st to 10th	Night	18% 19% 37% 23% 3	840
	11th to 20th	Night	20% 17% 36% 21% 5%	840
	21st to end	Night	20% 15% 39% 24% 2	924
February	1st to 10th	Night	21% 12% 43% 22% 3	840
	11th to 20th	Night	26% 18% 38% 17% 2	823
	21st to end	Night	20% 17% 39% 21% 3	692
March	1st to 10th	Night	17% 15% 36% 27% 4	840
	11th to 20th	Night	21% 15% 37% 22% 5%	840
	21st to end	Night	19% 13% 42% 22% 5%	924
April	1st to 10th	Night	17% 16% 41% 21% 5%	840
	11th to 20th	Night	15% 10% 41% 24% 9% 1	831
	21st to end	Night	16% 10% 35% 32% 6%	840
May	1st to 10th	Night	16% 12% 37% 29% 6% 1	805
	11th to 20th	Night	17% 6% 28% 39% 10%	503
	21st to end	Night	15% 2 23% 40% 18% 2	433
June	1st to 10th	Night	12% 3 20% 45% 18% 3	400
	11th to 20th	Night	11% 3 22% 42% 20% 2	400
	21st to end	Night	7% 5% 18% 47% 22% 1	400
July	1st to 10th	Night	10% 3 16% 46% 24% 2	390
	11th to 20th	Night	8% 2 11% 42% 32% 4	528
	21st to end	Night	8% 3 18% 41% 26% 3	657
August	1st to 10th	Night	12% 2 16% 40% 28% 3	597
	11th to 20th	Night	12% 3 14% 39% 27% 4	767
	21st to end	Night	11% 2 15% 37% 29% 6%	880
September	1st to 10th	Night	14% 3 17% 36% 26% 5%	800
	11th to 20th	Night	15% 4 17% 34% 26% 5%	800
	21st to end	Night	23% 5% 19% 34% 18% 2	800
October	1st to 10th	Night	19% 6% 19% 29% 23% 5%	800
	11th to 20th	Night	19% 10% 25% 29% 15% 2	800
	21st to end	Night	16% 9% 30% 27% 16% 2	880
November	1st to 10th	Night	17% 10% 27% 30% 15% 2	820
	11th to 20th	Night	17% 12% 33% 28% 10% 1	840
	21st to end	Night	13% 14% 32% 29% 10% 1	840
December	1st to 10th	Night	20% 13% 34% 24% 8% 1	840
	11th to 20th	Night	20% 12% 36% 27% 5%	840
	21st to end	Night	19% 13% 31% 31% 6%	924

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