Chesapeake Beach Veterans Memorial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chesapeake Beach Veterans Memorial Park clear sky chart from 2005-11-06 to 2024-11-01.

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	14% 6% 2 5% 4 4 4 4 6% 8% 43%	101165
	Night	15% 6% 2 6% 4 4 4 4 5% 7% 43%	97749
Transparency	Day	21% 49% 7% 13% 8% 1	100962
	Night	22% 49% 6% 13% 8% 2	97622
Seeing	Day	17% 12% 29% 26% 13% 3	15048
	Night	17% 13% 29% 28% 12% 1	24501

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	16% 5% 2 5% 2 3 3 3 5% 7% 48%	2526
	11th to 20th	Day	14% 10% 3 7% 4 4 4 3 4 5% 41%	2840
	21st to end	Day	17% 7% 2 7% 4 4 4 4 5% 7% 39%	3124
February	1st to 10th	Day	14% 6% 3 6% 4 5% 4 4 7% 7% 39%	1710
	11th to 20th	Day	18% 7% 2 4 3 3 3 3 5% 7% 44%	1761
	21st to end	Day	17% 9% 2 6% 5% 4 5% 4 5% 6% 39%	1570
March	1st to 10th	Day	23% 6% 2 4 4 4 4 3 5% 8% 39%	3303
	11th to 20th	Day	10% 4 2 4 3 4 4 4 5% 8% 53%	3480
	21st to end	Day	20% 7% 2 5% 4 3 4 3 5% 6% 41%	3932
April	1st to 10th	Day	13% 7% 2 4 4 5% 4 4 7% 8% 43%	2280
	11th to 20th	Day	12% 5% 1 5% 3 4 5% 3 5% 6% 49%	2254
	21st to end	Day	17% 6% 2 4 3 4 4 4 5% 7% 44%	2280
May	1st to 10th	Day	23% 7% 3 6% 4 4 4 4 6% 8% 31%	3911
	11th to 20th	Day	21% 6% 2 5% 4 4 4 4 6% 8% 35%	4356
	21st to end	Day	10% 4 1 5% 4 4 4 4 7% 10% 47%	4823
June	1st to 10th	Day	10% 4 1 5% 4 4 5% 4 7% 10% 45%	2660
	11th to 20th	Day	10% 4 2 5% 3 5% 5% 4 7% 10% 44%	2660
	21st to end	Day	9% 3 1 4 4 4 6% 6% 7% 11% 45%	2660
July	1st to 10th	Day	5% 4 2 5% 4 5% 6% 6% 8% 11% 44%	4440
	11th to 20th	Day	9% 5% 2 6% 4 5% 5% 5% 8% 11% 40%	4383
	21st to end	Day	8% 6% 2 8% 5% 5% 6% 5% 8% 9% 37%	4466
August	1st to 10th	Day	15% 6% 2 6% 4 5% 5% 5% 8% 12% 34%	4104
	11th to 20th	Day	9% 5% 2 6% 4 5% 6% 4 7% 9% 42%	3795
	21st to end	Day	8% 4 2 5% 3 3 4 4 6% 10% 49%	4180
September	1st to 10th	Day	13% 4 2 5% 4 4 4 4 5% 8% 47%	2280
	11th to 20th	Day	12% 6% 2 4 4 4 3 3 5% 8% 49%	2280
	21st to end	Day	20% 8% 3 5% 3 4 4 3 6% 6% 38%	2024
October	1st to 10th	Day	17% 4 2 4 3 3 4 3 5% 7% 48%	1900
	11th to 20th	Day	18% 3 1 3 2 3 4 2 5% 7% 52%	1900
	21st to end	Day	13% 5% 1 6% 3 3 4 3 4 7% 51%	2090
November	1st to 10th	Day	13% 5% 1 3 4 3 4 3 4 7% 53%	1723
	11th to 20th	Day	14% 6% 2 3 3 3 4 3 5% 7% 50%	1710
	21st to end	Day	14% 6% 1 5% 4 3 4 3 4 7% 49%	1558
December	1st to 10th	Day	16% 5% 2 5% 4 3 4 4 5% 6% 44%	1520
	11th to 20th	Day	15% 8% 3 5% 3 3 3 3 5% 6% 47%	1910
	21st to end	Day	16% 7% 2 6% 3 5% 5% 4 6% 7% 39%	2772
January	1st to 10th	Night	15% 7% 2 5% 3 4 4 3 5% 6% 45%	4415
	11th to 20th	Night	17% 8% 2 6% 3 3 3 3 4 5% 46%	4120
	21st to end	Night	18% 9% 3 6% 4 3 3 3 4 5% 42%	4532
February	1st to 10th	Night	16% 7% 2 6% 4 4 4 4 5% 6% 43%	2470
	11th to 20th	Night	19% 7% 2 6% 3 3 3 3 4 6% 44%	2305
	21st to end	Night	18% 8% 3 5% 3 3 3 3 5% 6% 44%	1884
March	1st to 10th	Night	21% 7% 2 7% 4 3 3 3 4 6% 39%	3547
	11th to 20th	Night	12% 4 1 4 3 4 4 4 6% 7% 50%	3480
	21st to end	Night	16% 7% 3 7% 4 3 3 3 4 5% 46%	3700
April	1st to 10th	Night	16% 7% 1 5% 5% 4 4 4 6% 6% 42%	1900
	11th to 20th	Night	12% 5% 2 6% 4 3 4 4 5% 7% 48%	1875
	21st to end	Night	18% 5% 2 5% 3 3 4 4 6% 7% 43%	1900
May	1st to 10th	Night	20% 8% 3 7% 5% 4 4 4 5% 7% 32%	3013
	11th to 20th	Night	25% 7% 2 6% 4 4 4 3 5% 7% 31%	2537
	21st to end	Night	11% 5% 2 5% 5% 4 5% 3 6% 10% 44%	2732
June	1st to 10th	Night	11% 4 2 6% 5% 4 4 4 6% 10% 43%	1520
	11th to 20th	Night	11% 6% 2 6% 4 5% 4 4 6% 11% 41%	1520
	21st to end	Night	9% 5% 2 5% 5% 4 6% 4 7% 12% 40%	1520
July	1st to 10th	Night	6% 6% 2 6% 6% 5% 6% 6% 8% 11% 39%	2520
	11th to 20th	Night	9% 6% 2 7% 5% 5% 6% 5% 7% 11% 38%	2574
	21st to end	Night	10% 8% 3 9% 6% 5% 6% 5% 6% 7% 36%	3087
August	1st to 10th	Night	15% 5% 3 8% 5% 5% 6% 4 7% 11% 33%	2825
	11th to 20th	Night	11% 6% 3 8% 6% 6% 6% 5% 7% 9% 34%	3001
	21st to end	Night	10% 5% 2 6% 3 3 4 4 6% 8% 50%	3476
September	1st to 10th	Night	14% 5% 2 6% 5% 3 4 3 6% 6% 45%	1900
	11th to 20th	Night	11% 5% 1 5% 4 4 4 3 6% 8% 48%	1900
	21st to end	Night	21% 8% 2 6% 4 3 4 3 6% 6% 37%	2152
October	1st to 10th	Night	18% 5% 2 5% 3 3 4 4 5% 6% 45%	2280
	11th to 20th	Night	16% 5% 2 4 3 3 3 3 3 6% 52%	2280
	21st to end	Night	15% 4 2 5% 3 4 4 3 5% 6% 50%	2508
November	1st to 10th	Night	13% 6% 2 5% 3 3 4 3 5% 5% 53%	2360
	11th to 20th	Night	16% 6% 2 4 3 3 4 2 4 6% 49%	2470
	21st to end	Night	13% 5% 2 4 4 3 4 4 6% 6% 50%	2617
December	1st to 10th	Night	17% 7% 3 6% 3 4 4 3 5% 7% 41%	2660
	11th to 20th	Night	16% 5% 2 6% 4 4 4 3 5% 6% 43%	3285
	21st to end	Night	16% 7% 2 6% 4 4 5% 5% 6% 7% 38%	4884

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% 4 23% 11% 3	2527
	11th to 20th	Day	28% 38% 6% 13% 11% 4	2840
	21st to end	Day	29% 42% 9% 12% 6% 1	3124
February	1st to 10th	Day	17% 66% 5% 8% 4	1710
	11th to 20th	Day	15% 64% 4 9% 6% 2	1770
	21st to end	Day	18% 65% 5% 5% 6% 1	1570
March	1st to 10th	Day	32% 43% 5% 11% 5% 2	3303
	11th to 20th	Day	13% 42% 5% 21% 17% 2	3480
	21st to end	Day	27% 42% 6% 12% 11% 2	3932
April	1st to 10th	Day	15% 66% 4 7% 7% 1	2280
	11th to 20th	Day	12% 67% 4 9% 7% 1	2254
	21st to end	Day	15% 66% 4 9% 6% 1	2280
May	1st to 10th	Day	34% 44% 6% 12% 3 1	3946
	11th to 20th	Day	30% 43% 10% 14% 3	4360
	21st to end	Day	17% 44% 9% 16% 12% 2	4837
June	1st to 10th	Day	13% 67% 4 10% 5% 1	2660
	11th to 20th	Day	10% 67% 5% 9% 8% 1	2660
	21st to end	Day	10% 66% 7% 10% 7% 1	2660
July	1st to 10th	Day	21% 38% 19% 11% 7% 4	4370
	11th to 20th	Day	27% 37% 13% 18% 4 1	4308
	21st to end	Day	30% 37% 8% 14% 11% 1	4324
August	1st to 10th	Day	31% 38% 12% 16% 3	4091
	11th to 20th	Day	25% 37% 8% 22% 7% 1	3833
	21st to end	Day	18% 37% 10% 21% 13% 1	4180
September	1st to 10th	Day	15% 62% 6% 10% 6% 2	2280
	11th to 20th	Day	15% 61% 5% 10% 8% 2	2280
	21st to end	Day	23% 60% 3 10% 3 1	2024
October	1st to 10th	Day	14% 61% 5% 12% 7% 1	1900
	11th to 20th	Day	12% 60% 3 12% 11% 2	1900
	21st to end	Day	11% 59% 4 12% 10% 3	2090
November	1st to 10th	Day	16% 60% 5% 10% 7% 3	1723
	11th to 20th	Day	13% 59% 3 12% 11% 2	1710
	21st to end	Day	14% 60% 3 14% 8% 1	1558
December	1st to 10th	Day	20% 61% 6% 8% 3 2	1520
	11th to 20th	Day	19% 49% 4 18% 8% 2	1906
	21st to end	Day	27% 42% 8% 16% 7%	2772
January	1st to 10th	Night	26% 38% 5% 16% 12% 3	4415
	11th to 20th	Night	26% 37% 4 17% 13% 3	4120
	21st to end	Night	30% 40% 4 15% 9% 1	4532
February	1st to 10th	Night	16% 67% 5% 9% 3 1	2470
	11th to 20th	Night	16% 63% 2 7% 9% 2	2307
	21st to end	Night	15% 64% 4 9% 5% 2	1884
March	1st to 10th	Night	34% 42% 4 13% 6% 1	3547
	11th to 20th	Night	14% 42% 5% 21% 14% 3	3480
	21st to end	Night	25% 41% 4 13% 14% 4	3700
April	1st to 10th	Night	16% 65% 3 7% 8% 1	1900
	11th to 20th	Night	14% 66% 4 10% 5% 2	1875
	21st to end	Night	16% 66% 3 8% 6% 1	1900
May	1st to 10th	Night	34% 44% 6% 11% 5%	3043
	11th to 20th	Night	33% 44% 7% 13% 2	2538
	21st to end	Night	19% 44% 10% 15% 10% 2	2739
June	1st to 10th	Night	14% 66% 4 8% 7%	1520
	11th to 20th	Night	13% 66% 5% 9% 6% 1	1520
	21st to end	Night	12% 65% 5% 10% 7% 1	1520
July	1st to 10th	Night	25% 40% 17% 10% 7% 1	2480
	11th to 20th	Night	28% 36% 15% 16% 4	2526
	21st to end	Night	34% 36% 9% 13% 8%	2988
August	1st to 10th	Night	34% 38% 11% 13% 4	2814
	11th to 20th	Night	29% 38% 8% 18% 7%	3029
	21st to end	Night	18% 37% 5% 21% 18%	3476
September	1st to 10th	Night	15% 62% 6% 11% 5% 2	1900
	11th to 20th	Night	14% 60% 5% 11% 9% 2	1900
	21st to end	Night	23% 61% 4 8% 4	2152
October	1st to 10th	Night	18% 60% 5% 8% 7% 2	2280
	11th to 20th	Night	11% 60% 3 11% 11% 3	2280
	21st to end	Night	12% 59% 4 12% 9% 3	2508
November	1st to 10th	Night	16% 60% 4 11% 6% 3	2360
	11th to 20th	Night	14% 59% 3 8% 11% 3	2470
	21st to end	Night	12% 60% 5% 13% 9% 1	2617
December	1st to 10th	Night	20% 60% 6% 9% 3 1	2660
	11th to 20th	Night	19% 50% 4 13% 11% 3	3288
	21st to end	Night	27% 42% 9% 16% 6%	4884

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% 35% 15% 4 1	184
	11th to 20th	Day	23% 28% 32% 16% 1	270
	21st to end	Day	21% 22% 40% 15% 1 1	297
February	1st to 10th	Day	19% 23% 41% 12% 4	270
	11th to 20th	Day	27% 24% 37% 11% 1	368
	21st to end	Day	26% 23% 34% 14% 2	382
March	1st to 10th	Day	20% 23% 37% 17% 3 1	460
	11th to 20th	Day	20% 23% 36% 14% 5% 1	460
	21st to end	Day	22% 20% 36% 19% 3 1	506
April	1st to 10th	Day	17% 21% 40% 17% 5%	460
	11th to 20th	Day	13% 19% 34% 25% 7% 2	452
	21st to end	Day	20% 17% 34% 22% 7%	460
May	1st to 10th	Day	22% 15% 32% 21% 10%	463
	11th to 20th	Day	22% 10% 34% 25% 9% 1	487
	21st to end	Day	18% 5% 24% 31% 18% 4	529
June	1st to 10th	Day	11% 6% 29% 29% 21% 4	490
	11th to 20th	Day	11% 7% 28% 33% 17% 4	490
	21st to end	Day	9% 5% 29% 37% 16% 4	490
July	1st to 10th	Day	10% 3 19% 36% 25% 7%	485
	11th to 20th	Day	5% 1 15% 44% 28% 8%	484
	21st to end	Day	12% 3 20% 37% 23% 6%	532
August	1st to 10th	Day	14% 4 21% 32% 23% 7%	486
	11th to 20th	Day	13% 3 17% 38% 21% 9%	479
	21st to end	Day	9% 4 21% 34% 23% 10%	539
September	1st to 10th	Day	15% 5% 20% 29% 19% 12%	490
	11th to 20th	Day	15% 5% 21% 30% 21% 7%	490
	21st to end	Day	28% 9% 23% 27% 11% 2	490
October	1st to 10th	Day	20% 9% 23% 25% 18% 4	490
	11th to 20th	Day	18% 14% 25% 28% 14% 2	490
	21st to end	Day	14% 13% 35% 27% 8% 3	539
November	1st to 10th	Day	17% 13% 30% 25% 12% 4	390
	11th to 20th	Day	18% 17% 35% 20% 9% 1	370
	21st to end	Day	19% 21% 30% 20% 10%	218
December	1st to 10th	Day	19% 19% 42% 14% 4 1	180
	11th to 20th	Day	24% 19% 31% 20% 6%	180
	21st to end	Day	23% 16% 32% 25% 5%	198
January	1st to 10th	Night	18% 24% 36% 17% 4	760
	11th to 20th	Night	22% 17% 34% 21% 5%	760
	21st to end	Night	19% 21% 37% 21% 2	836
February	1st to 10th	Night	18% 18% 37% 24% 3	760
	11th to 20th	Night	23% 25% 36% 14% 1	743
	21st to end	Night	22% 21% 36% 18% 2	628
March	1st to 10th	Night	18% 19% 37% 22% 3	760
	11th to 20th	Night	22% 17% 36% 19% 6% 1	760
	21st to end	Night	19% 15% 41% 20% 5%	836
April	1st to 10th	Night	19% 21% 37% 20% 4	760
	11th to 20th	Night	15% 13% 37% 29% 7%	751
	21st to end	Night	22% 11% 31% 27% 9%	760
May	1st to 10th	Night	19% 8% 35% 27% 10% 1	695
	11th to 20th	Night	17% 8% 32% 33% 10%	403
	21st to end	Night	13% 4 24% 37% 20% 2	411
June	1st to 10th	Night	12% 3 26% 39% 19% 2	380
	11th to 20th	Night	11% 6% 19% 47% 16% 1	380
	21st to end	Night	10% 3 24% 46% 15% 2	380
July	1st to 10th	Night	9% 4 18% 39% 27% 3	370
	11th to 20th	Night	7% 1 14% 44% 31% 3	396
	21st to end	Night	9% 2 21% 40% 25% 4	624
August	1st to 10th	Night	10% 2 15% 44% 27% 3	567
	11th to 20th	Night	11% 3 18% 39% 27% 2	690
	21st to end	Night	12% 3 17% 33% 30% 5%	836
September	1st to 10th	Night	16% 3 19% 33% 25% 4	760
	11th to 20th	Night	12% 4 17% 37% 26% 4	760
	21st to end	Night	25% 6% 23% 28% 18% 1	760
October	1st to 10th	Night	20% 8% 20% 31% 17% 5%	760
	11th to 20th	Night	17% 13% 27% 27% 16% 1	760
	21st to end	Night	18% 12% 30% 25% 13% 1	836
November	1st to 10th	Night	15% 12% 34% 25% 12% 2	743
	11th to 20th	Night	18% 19% 31% 23% 8% 1	760
	21st to end	Night	16% 18% 31% 25% 9% 1	760
December	1st to 10th	Night	20% 20% 31% 19% 8% 1	760
	11th to 20th	Night	18% 16% 39% 21% 6%	760
	21st to end	Night	18% 18% 32% 28% 3	836

Page generated at 2024-10-29 11:20:46. Version ac07

Copyright © 2024 Attilla Danko.