Sandbank Stream Campground
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Sandbank Stream Campground clear sky chart from 2005-11-06 to 2024-12-24.

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	17% 9% 3 7% 5% 5% 5% 4 6% 7% 33%	101773
	Night	17% 9% 3 7% 5% 5% 5% 4 5% 6% 34%	98344
Transparency	Day	50% 6% 12% 20% 11% 1	105278
	Night	49% 6% 12% 21% 11% 1	102930
Seeing	Day	25% 16% 30% 20% 7% 2	15959
	Night	23% 13% 31% 25% 7%	24219

By Month

Percentage Cloud Cover NE (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	12% 13% 5% 9% 5% 4 5% 3 5% 5% 34%	2389
	11th to 20th	Day	14% 10% 6% 12% 5% 4 4 4 5% 4 32%	2520
	21st to end	Day	11% 11% 5% 11% 7% 6% 6% 4 5% 5% 30%	2772
February	1st to 10th	Day	12% 12% 5% 9% 8% 6% 6% 4 6% 6% 27%	1693
	11th to 20th	Day	13% 10% 4 12% 8% 5% 5% 5% 5% 6% 28%	1732
	21st to end	Day	13% 11% 4 10% 6% 5% 5% 4 5% 5% 33%	1570
March	1st to 10th	Day	21% 14% 3 8% 5% 4 4 3 5% 4 28%	3138
	11th to 20th	Day	16% 17% 4 9% 6% 5% 5% 3 5% 5% 24%	3480
	21st to end	Day	24% 12% 3 7% 5% 5% 3 2 4 6% 28%	3816
April	1st to 10th	Day	21% 12% 4 7% 5% 5% 5% 4 5% 6% 27%	2266
	11th to 20th	Day	19% 9% 3 7% 5% 5% 4 3 5% 6% 34%	2440
	21st to end	Day	22% 10% 3 7% 4 4 4 3 4 5% 33%	2470
May	1st to 10th	Day	17% 9% 3 8% 5% 5% 5% 4 6% 6% 32%	4106
	11th to 20th	Day	21% 8% 3 8% 5% 4 5% 4 6% 7% 30%	4142
	21st to end	Day	15% 7% 2 7% 6% 5% 6% 5% 7% 7% 31%	5154
June	1st to 10th	Day	22% 8% 3 7% 5% 5% 4 4 6% 7% 28%	2850
	11th to 20th	Day	18% 7% 2 6% 5% 5% 4 4 6% 7% 34%	2850
	21st to end	Day	25% 8% 3 6% 6% 4 6% 5% 6% 6% 26%	2850
July	1st to 10th	Day	14% 6% 2 6% 6% 6% 6% 5% 8% 9% 33%	4760
	11th to 20th	Day	15% 5% 2 7% 5% 5% 5% 4 6% 8% 37%	4457
	21st to end	Day	16% 6% 2 6% 5% 5% 5% 4 7% 7% 36%	4814
August	1st to 10th	Day	17% 6% 2 7% 5% 6% 6% 5% 7% 8% 32%	4113
	11th to 20th	Day	15% 9% 3 7% 5% 6% 6% 4 6% 8% 32%	4045
	21st to end	Day	15% 6% 2 6% 4 5% 5% 4 6% 8% 39%	4532
September	1st to 10th	Day	12% 5% 2 6% 4 4 5% 3 6% 8% 45%	2217
	11th to 20th	Day	15% 5% 2 6% 4 4 4 4 5% 5% 48%	2090
	21st to end	Day	17% 7% 2 6% 4 3 4 3 5% 7% 41%	2090
October	1st to 10th	Day	18% 7% 2 6% 5% 4 4 4 4 7% 38%	2023
	11th to 20th	Day	21% 9% 3 6% 4 4 4 3 6% 6% 33%	1867
	21st to end	Day	22% 10% 3 8% 4 4 4 3 5% 6% 29%	1881
November	1st to 10th	Day	19% 9% 2 7% 6% 5% 4 3 5% 6% 35%	1761
	11th to 20th	Day	18% 9% 2 8% 5% 4 4 3 5% 7% 34%	1680
	21st to end	Day	20% 11% 3 6% 5% 4 4 3 5% 8% 31%	1600
December	1st to 10th	Day	21% 12% 3 9% 6% 6% 4 4 4 6% 25%	1415
	11th to 20th	Day	22% 12% 3 7% 3 4 4 4 5% 5% 31%	1738
	21st to end	Day	21% 11% 3 8% 4 4 4 3 5% 6% 31%	2452
January	1st to 10th	Night	11% 11% 5% 11% 6% 6% 5% 4 5% 6% 30%	4556
	11th to 20th	Night	13% 10% 4 10% 6% 7% 7% 5% 6% 6% 27%	4440
	21st to end	Night	11% 12% 4 9% 6% 6% 6% 4 6% 7% 28%	4884
February	1st to 10th	Night	11% 13% 4 7% 6% 6% 5% 5% 6% 7% 31%	2485
	11th to 20th	Night	10% 12% 4 11% 6% 6% 5% 4 6% 7% 30%	2332
	21st to end	Night	15% 10% 3 8% 6% 5% 4 3 5% 6% 36%	1884
March	1st to 10th	Night	21% 12% 3 8% 5% 5% 5% 3 5% 5% 29%	3702
	11th to 20th	Night	15% 13% 4 9% 6% 6% 5% 5% 6% 7% 25%	3479
	21st to end	Night	25% 11% 3 6% 4 4 4 4 6% 7% 27%	3816
April	1st to 10th	Night	20% 13% 3 7% 5% 4 4 3 4 6% 32%	1911
	11th to 20th	Night	19% 9% 2 7% 3 4 4 3 5% 6% 39%	1689
	21st to end	Night	23% 10% 3 7% 5% 5% 4 3 5% 5% 32%	1710
May	1st to 10th	Night	22% 7% 2 6% 4 4 4 4 6% 7% 33%	2834
	11th to 20th	Night	19% 9% 3 10% 5% 6% 6% 5% 6% 7% 25%	2766
	21st to end	Night	15% 6% 2 5% 5% 4 4 5% 6% 9% 40%	2414
June	1st to 10th	Night	22% 9% 3 6% 5% 5% 4 4 5% 7% 31%	1330
	11th to 20th	Night	15% 6% 3 7% 5% 5% 5% 4 6% 8% 36%	1330
	21st to end	Night	25% 8% 2 7% 5% 3 4 3 6% 6% 32%	1330
July	1st to 10th	Night	13% 5% 2 5% 4 5% 5% 5% 6% 8% 40%	2210
	11th to 20th	Night	18% 5% 2 5% 4 4 4 4 5% 7% 41%	2487
	21st to end	Night	16% 7% 2 6% 4 3 4 3 7% 7% 41%	2739
August	1st to 10th	Night	20% 5% 2 7% 6% 5% 5% 4 6% 8% 32%	2784
	11th to 20th	Night	15% 7% 2 7% 4 5% 6% 5% 6% 8% 34%	2782
	21st to end	Night	14% 5% 2 7% 4 3 4 3 4 6% 49%	3124
September	1st to 10th	Night	13% 4 2 5% 4 4 4 3 5% 9% 47%	1957
	11th to 20th	Night	14% 6% 2 4 3 3 4 3 5% 7% 49%	2090
	21st to end	Night	17% 7% 3 6% 4 3 3 3 4 7% 44%	2090
October	1st to 10th	Night	18% 6% 2 6% 4 3 4 3 6% 6% 43%	2156
	11th to 20th	Night	18% 7% 2 7% 5% 4 4 4 5% 7% 38%	2310
	21st to end	Night	23% 8% 3 6% 4 4 4 3 4 6% 34%	2717
November	1st to 10th	Night	18% 7% 2 6% 4 4 5% 4 6% 8% 35%	2537
	11th to 20th	Night	17% 7% 3 8% 5% 4 4 3 6% 6% 37%	2720
	21st to end	Night	18% 10% 3 7% 5% 4 4 4 6% 6% 34%	2800
December	1st to 10th	Night	20% 12% 4 8% 4 4 5% 4 4 6% 28%	2980
	11th to 20th	Night	23% 9% 2 7% 5% 4 4 4 4 6% 32%	3681
	21st to end	Night	20% 11% 3 7% 5% 4 3 3 4 5% 34%	5288

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	50% 6% 15% 21% 8% 1	2390
	11th to 20th	Day	54% 5% 8% 22% 11% 1	2520
	21st to end	Day	54% 7% 10% 15% 13% 1	2772
February	1st to 10th	Day	56% 6% 10% 17% 9% 3	1693
	11th to 20th	Day	56% 5% 11% 15% 12% 1	1740
	21st to end	Day	53% 5% 8% 20% 10% 4	1570
March	1st to 10th	Day	59% 4 8% 12% 13% 3	3141
	11th to 20th	Day	60% 5% 12% 12% 9% 2	3480
	21st to end	Day	58% 3 6% 16% 14% 3	3816
April	1st to 10th	Day	57% 5% 9% 15% 11% 2	2266
	11th to 20th	Day	50% 5% 9% 19% 15% 2	2440
	21st to end	Day	53% 4 8% 18% 13% 4	2470
May	1st to 10th	Day	51% 7% 10% 21% 10% 2	4120
	11th to 20th	Day	52% 6% 15% 19% 8% 1	4146
	21st to end	Day	46% 9% 12% 16% 15%	5154
June	1st to 10th	Day	54% 7% 12% 17% 9% 1	2850
	11th to 20th	Day	47% 6% 12% 20% 12% 2	2850
	21st to end	Day	56% 8% 12% 15% 9% 1	2850
July	1st to 10th	Day	44% 8% 16% 21% 11%	4685
	11th to 20th	Day	44% 7% 13% 28% 8%	4381
	21st to end	Day	45% 7% 12% 28% 8% 1	4661
August	1st to 10th	Day	48% 8% 14% 24% 6%	4099
	11th to 20th	Day	48% 7% 17% 22% 6%	4084
	21st to end	Day	41% 7% 15% 24% 14%	4532
September	1st to 10th	Day	37% 6% 14% 26% 16% 1	2217
	11th to 20th	Day	37% 6% 11% 29% 17% 1	2090
	21st to end	Day	42% 6% 11% 27% 14% 1	2090
October	1st to 10th	Day	53% 5% 11% 22% 8%	3361
	11th to 20th	Day	47% 4 12% 29% 9%	3083
	21st to end	Day	41% 4 17% 20% 17%	3081
November	1st to 10th	Day	51% 5% 13% 19% 11% 1	1761
	11th to 20th	Day	50% 6% 12% 19% 11% 2	1680
	21st to end	Day	54% 5% 15% 19% 6% 1	1600
December	1st to 10th	Day	61% 4 11% 15% 8%	1415
	11th to 20th	Day	55% 4 11% 16% 13% 2	1738
	21st to end	Day	54% 5% 10% 18% 8% 4	2452
January	1st to 10th	Night	53% 8% 14% 16% 8% 1	4556
	11th to 20th	Night	54% 7% 11% 20% 7% 1	4440
	21st to end	Night	53% 7% 10% 17% 12% 1	4884
February	1st to 10th	Night	53% 5% 10% 19% 10% 2	2485
	11th to 20th	Night	52% 5% 12% 17% 12% 1	2335
	21st to end	Night	50% 4 10% 20% 13% 3	1884
March	1st to 10th	Night	58% 5% 8% 18% 8% 2	3712
	11th to 20th	Night	56% 9% 13% 14% 8% 1	3480
	21st to end	Night	56% 5% 7% 19% 12% 2	3816
April	1st to 10th	Night	55% 5% 7% 15% 15% 4	1911
	11th to 20th	Night	47% 4 10% 20% 15% 3	1689
	21st to end	Night	54% 4 9% 16% 14% 3	1710
May	1st to 10th	Night	47% 8% 15% 21% 9% 1	2840
	11th to 20th	Night	53% 10% 13% 17% 6% 1	2767
	21st to end	Night	40% 8% 17% 22% 13% 1	2415
June	1st to 10th	Night	52% 7% 11% 21% 8% 1	1330
	11th to 20th	Night	45% 7% 13% 21% 12% 2	1330
	21st to end	Night	54% 7% 12% 17% 9% 1	1330
July	1st to 10th	Night	39% 8% 19% 23% 11%	2175
	11th to 20th	Night	43% 6% 14% 29% 7%	2441
	21st to end	Night	42% 8% 15% 26% 9%	2651
August	1st to 10th	Night	51% 8% 13% 23% 5%	2774
	11th to 20th	Night	46% 8% 17% 21% 9%	2809
	21st to end	Night	39% 5% 14% 24% 17% 1	3124
September	1st to 10th	Night	34% 7% 13% 32% 13% 1	1957
	11th to 20th	Night	36% 6% 11% 31% 15% 1	2090
	21st to end	Night	41% 5% 11% 26% 15% 1	2090
October	1st to 10th	Night	48% 5% 11% 25% 11%	3598
	11th to 20th	Night	42% 5% 12% 30% 12%	3833
	21st to end	Night	42% 4 18% 21% 14% 1	4467
November	1st to 10th	Night	47% 6% 14% 23% 10% 1	2537
	11th to 20th	Night	48% 5% 13% 19% 13% 2	2720
	21st to end	Night	51% 7% 14% 17% 10% 1	2800
December	1st to 10th	Night	58% 5% 12% 18% 7%	2980
	11th to 20th	Night	54% 4 10% 17% 14% 1	3682
	21st to end	Night	53% 5% 11% 19% 10% 2	5288

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	23% 23% 32% 19% 3	180
	11th to 20th	Day	32% 21% 33% 9% 3 1	180
	21st to end	Day	19% 20% 38% 16% 7%	198
February	1st to 10th	Day	25% 19% 34% 17% 4 1	353
	11th to 20th	Day	25% 26% 32% 15% 2	399
	21st to end	Day	24% 23% 32% 20% 3	382
March	1st to 10th	Day	29% 20% 33% 16% 3	460
	11th to 20th	Day	26% 22% 30% 15% 6%	460
	21st to end	Day	31% 19% 27% 17% 5% 2	506
April	1st to 10th	Day	35% 19% 25% 15% 4 1	460
	11th to 20th	Day	31% 22% 27% 12% 7%	452
	21st to end	Day	33% 20% 29% 12% 5% 2	460
May	1st to 10th	Day	30% 19% 30% 17% 3 2	463
	11th to 20th	Day	27% 20% 30% 18% 5% 1	487
	21st to end	Day	23% 20% 31% 20% 5% 1	716
June	1st to 10th	Day	28% 15% 30% 17% 9% 1	680
	11th to 20th	Day	23% 13% 29% 23% 11% 1	680
	21st to end	Day	28% 10% 29% 23% 9% 1	680
July	1st to 10th	Day	18% 11% 33% 25% 10% 2	670
	11th to 20th	Day	19% 7% 40% 20% 12% 2	500
	21st to end	Day	16% 9% 33% 31% 9% 2	532
August	1st to 10th	Day	18% 8% 33% 28% 12% 3	486
	11th to 20th	Day	18% 10% 27% 29% 13% 4	479
	21st to end	Day	18% 12% 26% 29% 13% 3	539
September	1st to 10th	Day	14% 14% 30% 27% 12% 3	490
	11th to 20th	Day	20% 11% 24% 25% 13% 6%	490
	21st to end	Day	21% 13% 30% 20% 11% 5%	490
October	1st to 10th	Day	20% 13% 28% 22% 12% 5%	454
	11th to 20th	Day	28% 15% 30% 17% 7% 3	390
	21st to end	Day	30% 18% 26% 22% 4	429
November	1st to 10th	Day	31% 14% 28% 21% 7%	395
	11th to 20th	Day	28% 16% 35% 16% 6% 1	400
	21st to end	Day	31% 20% 27% 18% 4 1	400
December	1st to 10th	Day	27% 14% 35% 19% 4 1	215
	11th to 20th	Day	34% 22% 29% 11% 4 1	200
	21st to end	Day	30% 25% 25% 15% 4	204
January	1st to 10th	Night	21% 19% 35% 21% 3 1	796
	11th to 20th	Night	24% 18% 34% 20% 4	760
	21st to end	Night	15% 19% 38% 23% 4	836
February	1st to 10th	Night	20% 19% 37% 21% 3	760
	11th to 20th	Night	20% 22% 36% 18% 3	743
	21st to end	Night	23% 17% 32% 25% 3	628
March	1st to 10th	Night	23% 16% 37% 22% 2	760
	11th to 20th	Night	23% 16% 35% 20% 6%	760
	21st to end	Night	24% 16% 34% 20% 6%	836
April	1st to 10th	Night	30% 16% 32% 19% 4	760
	11th to 20th	Night	24% 16% 33% 21% 6%	565
	21st to end	Night	33% 13% 29% 20% 5%	570
May	1st to 10th	Night	26% 12% 33% 24% 4 1	570
	11th to 20th	Night	23% 14% 33% 23% 6%	541
	21st to end	Night	20% 10% 38% 26% 6%	411
June	1st to 10th	Night	24% 8% 30% 30% 7% 1	380
	11th to 20th	Night	17% 9% 28% 35% 11%	380
	21st to end	Night	28% 4 27% 34% 7%	380
July	1st to 10th	Night	19% 5% 33% 34% 10% 1	370
	11th to 20th	Night	18% 5% 27% 38% 12% 1	368
	21st to end	Night	20% 4 25% 39% 13%	416
August	1st to 10th	Night	19% 5% 25% 35% 16%	539
	11th to 20th	Night	16% 4 25% 36% 17% 1	562
	21st to end	Night	15% 7% 27% 34% 15% 2	627
September	1st to 10th	Night	16% 6% 34% 29% 14% 1	732
	11th to 20th	Night	18% 9% 24% 33% 14% 2	760
	21st to end	Night	22% 7% 30% 26% 14% 1	760
October	1st to 10th	Night	23% 9% 27% 29% 12% 1	760
	11th to 20th	Night	25% 11% 29% 25% 11%	760
	21st to end	Night	30% 14% 29% 22% 5%	836
November	1st to 10th	Night	26% 12% 32% 24% 7%	780
	11th to 20th	Night	23% 16% 30% 23% 7% 1	860
	21st to end	Night	27% 18% 27% 24% 4	900
December	1st to 10th	Night	29% 13% 34% 20% 4 1	900
	11th to 20th	Night	26% 19% 30% 21% 4	900
	21st to end	Night	27% 17% 33% 19% 3	953

Page generated at 2024-12-21 04:13:49. Version ac07

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