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 2025-01-07.

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	13% 6% 2 6% 4 4 4 4 6% 8% 43%	104670
	Night	14% 6% 2 6% 4 4 4 3 5% 7% 43%	104322
Transparency	Day	21% 46% 8% 13% 10% 2	108306
	Night	22% 45% 6% 13% 11% 3	108825
Seeing	Day	16% 11% 28% 26% 15% 4	15386
	Night	17% 10% 29% 30% 13% 2	25050

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	17% 5% 1 4 2 3 3 2 4 4 53%	2726
	11th to 20th	Day	13% 7% 2 6% 4 3 3 3 5% 6% 47%	2840
	21st to end	Day	14% 10% 3 7% 5% 4 3 4 4 6% 41%	3124
February	1st to 10th	Day	12% 9% 3 6% 4 5% 5% 4 6% 6% 40%	1710
	11th to 20th	Day	21% 6% 2 4 2 3 3 3 4 6% 46%	1793
	21st to end	Day	16% 8% 3 5% 4 4 5% 4 7% 6% 37%	1570
March	1st to 10th	Day	22% 10% 3 6% 4 3 4 3 4 6% 36%	3337
	11th to 20th	Day	10% 5% 2 4 3 3 3 3 5% 7% 55%	3480
	21st to end	Day	18% 7% 2 5% 4 4 4 3 5% 6% 43%	3924
April	1st to 10th	Day	12% 5% 2 5% 4 4 3 2 5% 6% 52%	2280
	11th to 20th	Day	9% 6% 2 6% 5% 3 4 4 6% 7% 49%	2254
	21st to end	Day	13% 7% 2 6% 4 4 4 4 5% 7% 44%	2280
May	1st to 10th	Day	14% 8% 3 8% 5% 5% 5% 4 6% 9% 34%	3792
	11th to 20th	Day	18% 7% 3 7% 5% 4 5% 4 5% 8% 34%	4227
	21st to end	Day	9% 5% 2 5% 3 4 4 4 7% 10% 48%	4823
June	1st to 10th	Day	10% 4 2 5% 4 5% 5% 5% 7% 10% 43%	2660
	11th to 20th	Day	10% 6% 2 5% 4 5% 5% 4 7% 10% 43%	2660
	21st to end	Day	7% 5% 2 6% 5% 5% 6% 5% 7% 12% 41%	2660
July	1st to 10th	Day	5% 4 2 6% 5% 5% 7% 6% 9% 13% 40%	4440
	11th to 20th	Day	12% 7% 3 7% 5% 5% 5% 4 7% 11% 35%	4196
	21st to end	Day	8% 7% 3 8% 6% 6% 6% 6% 8% 10% 32%	4466
August	1st to 10th	Day	14% 8% 4 7% 5% 6% 6% 5% 7% 10% 27%	4104
	11th to 20th	Day	10% 6% 2 7% 5% 6% 6% 5% 7% 9% 36%	3731
	21st to end	Day	8% 5% 1 5% 4 4 5% 4 8% 11% 46%	4180
September	1st to 10th	Day	13% 5% 2 5% 4 4 5% 4 6% 9% 41%	2280
	11th to 20th	Day	14% 6% 3 6% 4 5% 5% 4 6% 6% 42%	2280
	21st to end	Day	20% 8% 3 6% 4 4 4 3 5% 6% 37%	2026
October	1st to 10th	Day	16% 6% 2 5% 4 3 4 3 5% 6% 45%	1900
	11th to 20th	Day	13% 7% 2 5% 3 3 3 3 4 5% 52%	1900
	21st to end	Day	12% 4 3 6% 3 3 3 3 4 6% 52%	2090
November	1st to 10th	Day	14% 5% 2 5% 4 3 4 2 4 7% 51%	1872
	11th to 20th	Day	14% 7% 2 4 3 2 3 3 5% 7% 50%	1800
	21st to end	Day	14% 4 2 4 3 3 3 3 5% 7% 51%	1715
December	1st to 10th	Day	11% 5% 2 5% 3 3 3 3 5% 6% 54%	2600
	11th to 20th	Day	15% 9% 3 5% 4 3 3 3 4 5% 47%	2990
	21st to end	Day	13% 5% 2 5% 3 3 3 3 5% 7% 49%	3960
January	1st to 10th	Night	13% 7% 2 6% 4 4 4 3 5% 5% 47%	4348
	11th to 20th	Night	16% 8% 3 7% 4 4 3 3 5% 5% 43%	4120
	21st to end	Night	19% 8% 2 7% 4 3 3 3 5% 5% 43%	4532
February	1st to 10th	Night	16% 7% 2 6% 4 3 4 3 5% 6% 43%	2470
	11th to 20th	Night	20% 7% 2 6% 4 3 4 2 5% 5% 41%	2271
	21st to end	Night	17% 7% 2 6% 4 3 3 3 4 6% 46%	1884
March	1st to 10th	Night	24% 8% 3 7% 4 3 4 3 4 5% 35%	3513
	11th to 20th	Night	14% 6% 2 5% 3 3 3 3 5% 6% 50%	3480
	21st to end	Night	17% 7% 3 6% 4 3 3 3 3 4 48%	3706
April	1st to 10th	Night	13% 6% 3 6% 4 4 4 3 6% 7% 43%	1900
	11th to 20th	Night	13% 6% 2 4 4 4 3 3 5% 7% 49%	1875
	21st to end	Night	14% 7% 2 5% 4 3 4 3 5% 7% 45%	1900
May	1st to 10th	Night	16% 8% 2 9% 5% 5% 5% 4 5% 7% 34%	3130
	11th to 20th	Night	20% 7% 2 6% 5% 4 4 4 6% 7% 35%	2664
	21st to end	Night	11% 5% 2 6% 5% 4 4 3 5% 9% 45%	2732
June	1st to 10th	Night	12% 5% 1 6% 4 5% 5% 4 8% 11% 39%	1520
	11th to 20th	Night	9% 5% 2 5% 5% 4 6% 5% 8% 9% 42%	1520
	21st to end	Night	8% 5% 2 6% 6% 5% 5% 5% 7% 8% 42%	1520
July	1st to 10th	Night	8% 4 2 6% 5% 5% 6% 5% 8% 11% 39%	2520
	11th to 20th	Night	10% 7% 2 7% 4 5% 6% 6% 7% 11% 36%	2760
	21st to end	Night	14% 9% 4 9% 6% 5% 5% 4 7% 9% 30%	3087
August	1st to 10th	Night	17% 8% 3 7% 5% 5% 5% 5% 7% 9% 30%	2825
	11th to 20th	Night	9% 6% 3 8% 5% 5% 5% 4 7% 9% 40%	3063
	21st to end	Night	8% 5% 2 5% 4 4 4 3 7% 11% 46%	3476
September	1st to 10th	Night	12% 4 2 5% 5% 3 5% 4 7% 8% 45%	1900
	11th to 20th	Night	12% 7% 2 6% 4 5% 4 3 5% 7% 44%	1900
	21st to end	Night	19% 7% 3 8% 4 4 4 3 5% 5% 37%	2149
October	1st to 10th	Night	14% 6% 2 6% 4 4 4 3 4 5% 47%	2280
	11th to 20th	Night	15% 6% 2 5% 3 3 3 3 4 6% 50%	2280
	21st to end	Night	14% 5% 1 4 3 4 3 3 5% 6% 52%	2508
November	1st to 10th	Night	14% 6% 2 5% 3 3 4 2 5% 5% 50%	2426
	11th to 20th	Night	15% 6% 2 5% 3 3 4 3 4 6% 48%	2600
	21st to end	Night	12% 4 2 5% 4 3 4 3 6% 6% 50%	2682
December	1st to 10th	Night	10% 5% 2 5% 3 4 4 3 4 6% 54%	4580
	11th to 20th	Night	17% 8% 3 7% 5% 4 4 4 5% 5% 39%	5205
	21st to end	Night	12% 6% 2 6% 4 3 4 3 5% 7% 48%	6996

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	22% 37% 2 21% 15% 3	2727
	11th to 20th	Day	23% 38% 5% 12% 19% 3	2840
	21st to end	Day	30% 41% 7% 11% 10% 1	3124
February	1st to 10th	Day	15% 66% 4 10% 5% 1	1710
	11th to 20th	Day	16% 65% 3 8% 6% 3	1802
	21st to end	Day	17% 65% 5% 5% 5% 2	1570
March	1st to 10th	Day	35% 43% 6% 5% 7% 3	3337
	11th to 20th	Day	14% 41% 5% 15% 19% 6%	3480
	21st to end	Day	25% 41% 8% 10% 12% 2	3924
April	1st to 10th	Day	13% 66% 4 8% 8% 1	2280
	11th to 20th	Day	12% 66% 5% 9% 6% 1	2254
	21st to end	Day	14% 65% 5% 8% 5% 2	2280
May	1st to 10th	Day	30% 45% 10% 11% 4 1	3827
	11th to 20th	Day	29% 44% 9% 14% 4	4231
	21st to end	Day	15% 43% 11% 16% 12% 2	4837
June	1st to 10th	Day	13% 67% 6% 8% 6% 1	2660
	11th to 20th	Day	10% 66% 6% 10% 7%	2660
	21st to end	Day	11% 65% 6% 11% 7%	2660
July	1st to 10th	Day	21% 41% 18% 11% 6% 2	4370
	11th to 20th	Day	31% 39% 16% 11% 2	4124
	21st to end	Day	31% 40% 8% 10% 10% 1	4324
August	1st to 10th	Day	36% 40% 11% 11% 2	4091
	11th to 20th	Day	25% 42% 9% 18% 7%	3767
	21st to end	Day	16% 39% 11% 21% 13% 1	4180
September	1st to 10th	Day	15% 63% 8% 8% 5% 2	2280
	11th to 20th	Day	18% 61% 5% 7% 7% 2	2280
	21st to end	Day	23% 60% 3 10% 3	2026
October	1st to 10th	Day	18% 39% 8% 16% 17% 2	3160
	11th to 20th	Day	11% 37% 3 12% 31% 7%	3140
	21st to end	Day	9% 36% 6% 21% 18% 11%	3428
November	1st to 10th	Day	18% 56% 4 13% 8% 2	1872
	11th to 20th	Day	16% 57% 4 8% 12% 3	1800
	21st to end	Day	15% 57% 3 12% 11% 2	1715
December	1st to 10th	Day	20% 37% 4 20% 15% 4	2600
	11th to 20th	Day	29% 32% 10% 13% 13% 4	2986
	21st to end	Day	25% 28% 11% 23% 13% 1	3960
January	1st to 10th	Night	25% 37% 5% 15% 14% 4	4348
	11th to 20th	Night	27% 38% 3 14% 16% 2	4120
	21st to end	Night	29% 40% 4 11% 11% 4	4532
February	1st to 10th	Night	14% 65% 6% 9% 5% 1	2470
	11th to 20th	Night	18% 64% 2 8% 6% 2	2273
	21st to end	Night	15% 64% 3 9% 6% 2	1884
March	1st to 10th	Night	37% 43% 4 9% 6% 1	3513
	11th to 20th	Night	18% 41% 4 12% 18% 7%	3480
	21st to end	Night	24% 41% 3 17% 12% 3	3706
April	1st to 10th	Night	15% 66% 4 5% 9% 1	1900
	11th to 20th	Night	13% 66% 4 9% 6% 1	1875
	21st to end	Night	15% 65% 5% 8% 5% 1	1900
May	1st to 10th	Night	31% 44% 8% 11% 5%	3160
	11th to 20th	Night	29% 44% 8% 15% 3	2665
	21st to end	Night	20% 44% 12% 15% 10% 1	2739
June	1st to 10th	Night	15% 67% 6% 7% 5% 1	1520
	11th to 20th	Night	10% 67% 8% 9% 7%	1520
	21st to end	Night	12% 66% 5% 9% 8% 1	1520
July	1st to 10th	Night	25% 44% 12% 12% 6% 1	2480
	11th to 20th	Night	29% 41% 14% 15% 2	2709
	21st to end	Night	37% 39% 6% 9% 9%	2988
August	1st to 10th	Night	36% 39% 11% 11% 2	2814
	11th to 20th	Night	23% 41% 12% 16% 8%	3093
	21st to end	Night	18% 38% 6% 18% 19% 1	3476
September	1st to 10th	Night	14% 62% 10% 7% 4 1	1900
	11th to 20th	Night	17% 61% 4 9% 7% 1	1900
	21st to end	Night	24% 61% 4 8% 3	2149
October	1st to 10th	Night	23% 38% 8% 14% 15% 2	3800
	11th to 20th	Night	11% 37% 4 13% 25% 9%	3779
	21st to end	Night	8% 36% 4 24% 18% 10%	4120
November	1st to 10th	Night	20% 56% 4 11% 8% 2	2426
	11th to 20th	Night	16% 57% 3 9% 9% 6%	2600
	21st to end	Night	14% 57% 4 12% 12% 2	2682
December	1st to 10th	Night	19% 36% 4 20% 17% 4	4580
	11th to 20th	Night	35% 33% 7% 11% 10% 5%	5208
	21st to end	Night	27% 28% 11% 22% 12% 1	6996

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% 20% 38% 13% 5%	238
	11th to 20th	Day	24% 24% 35% 13% 4	270
	21st to end	Day	18% 24% 39% 16% 3	297
February	1st to 10th	Day	16% 21% 41% 17% 4	270
	11th to 20th	Day	27% 24% 34% 13% 2	401
	21st to end	Day	23% 21% 37% 17% 3	382
March	1st to 10th	Day	18% 21% 40% 16% 5%	460
	11th to 20th	Day	22% 19% 35% 18% 5% 1	460
	21st to end	Day	21% 17% 39% 18% 6% 1	506
April	1st to 10th	Day	17% 20% 39% 16% 6% 1	460
	11th to 20th	Day	11% 15% 38% 24% 8% 3	452
	21st to end	Day	18% 13% 36% 24% 8% 1	460
May	1st to 10th	Day	13% 17% 37% 22% 10% 2	463
	11th to 20th	Day	20% 8% 30% 27% 13% 2	487
	21st to end	Day	19% 4 23% 28% 21% 5%	529
June	1st to 10th	Day	11% 4 25% 33% 22% 4	490
	11th to 20th	Day	12% 6% 22% 32% 22% 6%	490
	21st to end	Day	8% 4 18% 44% 21% 5%	490
July	1st to 10th	Day	9% 2 12% 39% 30% 7%	485
	11th to 20th	Day	8% 2 13% 36% 32% 9%	484
	21st to end	Day	9% 2 21% 35% 27% 6%	532
August	1st to 10th	Day	14% 3 19% 34% 23% 7%	486
	11th to 20th	Day	13% 3 18% 32% 25% 9%	479
	21st to end	Day	8% 4 17% 31% 28% 12%	539
September	1st to 10th	Day	15% 2 22% 26% 21% 14%	490
	11th to 20th	Day	15% 4 21% 29% 21% 10%	490
	21st to end	Day	27% 8% 22% 24% 14% 4	490
October	1st to 10th	Day	19% 5% 23% 27% 19% 7%	490
	11th to 20th	Day	14% 12% 26% 28% 16% 3	490
	21st to end	Day	13% 11% 33% 27% 11% 5%	539
November	1st to 10th	Day	17% 8% 30% 27% 14% 4	452
	11th to 20th	Day	18% 17% 32% 23% 10% 1	400
	21st to end	Day	19% 17% 29% 21% 12% 2	315
December	1st to 10th	Day	20% 16% 42% 17% 4 2	200
	11th to 20th	Day	22% 14% 39% 19% 8%	200
	21st to end	Day	20% 20% 31% 19% 9%	220
January	1st to 10th	Night	18% 19% 36% 23% 4	785
	11th to 20th	Night	21% 16% 35% 22% 6%	760
	21st to end	Night	20% 14% 39% 25% 2	836
February	1st to 10th	Night	19% 12% 42% 23% 3	760
	11th to 20th	Night	24% 19% 38% 17% 2	743
	21st to end	Night	20% 16% 39% 21% 3	628
March	1st to 10th	Night	18% 15% 36% 27% 5%	760
	11th to 20th	Night	22% 15% 37% 21% 5%	760
	21st to end	Night	19% 12% 41% 23% 5%	836
April	1st to 10th	Night	18% 15% 41% 21% 5%	760
	11th to 20th	Night	16% 10% 39% 25% 9% 1	751
	21st to end	Night	16% 10% 36% 32% 6%	760
May	1st to 10th	Night	17% 11% 36% 30% 6% 1	760
	11th to 20th	Night	16% 6% 28% 39% 10%	478
	21st to end	Night	14% 2 22% 41% 19% 2	411
June	1st to 10th	Night	12% 3 21% 44% 18% 3	380
	11th to 20th	Night	9% 3 22% 42% 21% 2	380
	21st to end	Night	7% 5% 19% 47% 21% 1	380
July	1st to 10th	Night	9% 3 16% 46% 24% 2	370
	11th to 20th	Night	9% 2 12% 42% 32% 4	501
	21st to end	Night	9% 4 18% 43% 24% 3	624
August	1st to 10th	Night	11% 2 15% 41% 28% 3	567
	11th to 20th	Night	12% 3 14% 39% 27% 4	728
	21st to end	Night	11% 1 14% 37% 30% 6%	836
September	1st to 10th	Night	14% 3 16% 36% 27% 5%	760
	11th to 20th	Night	15% 4 17% 33% 26% 5%	760
	21st to end	Night	23% 5% 19% 33% 18% 2	760
October	1st to 10th	Night	19% 6% 19% 29% 23% 5%	760
	11th to 20th	Night	18% 10% 25% 30% 16% 2	760
	21st to end	Night	15% 8% 30% 28% 17% 2	836
November	1st to 10th	Night	17% 9% 26% 30% 16% 2	780
	11th to 20th	Night	18% 12% 32% 28% 10% 1	800
	21st to end	Night	14% 13% 32% 29% 11% 1	800
December	1st to 10th	Night	20% 13% 35% 23% 8% 1	800
	11th to 20th	Night	20% 11% 36% 27% 6%	800
	21st to end	Night	19% 12% 30% 32% 6%	880

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