Weber County North Fork Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Weber County North Fork Park clear sky chart from 2005-11-06 to 2026-08-15.

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	6% 9% 3 6% 4 3 4 3 5% 6% 52%	152592
	Night	7% 9% 3 7% 4 4 4 3 5% 6% 49%	146844
Transparency	Day	33% 4 9% 19% 21% 13%	147326
	Night	35% 4 10% 20% 20% 10%	143129
Seeing	Day	14% 14% 31% 27% 11% 3	17617
	Night	14% 6% 19% 36% 21% 3	27499

By Month

Percentage Cloud Cover SW (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	7% 25% 6% 11% 4 3 4 3 4 4 27%	5318
	11th to 20th	Day	5% 12% 5% 10% 5% 4 4 2 3 5% 45%	5340
	21st to end	Day	5% 13% 5% 9% 4 3 3 3 4 5% 47%	5844
February	1st to 10th	Day	14% 18% 4 10% 4 4 4 3 5% 5% 30%	1890
	11th to 20th	Day	9% 22% 6% 10% 6% 4 4 2 4 5% 28%	1907
	21st to end	Day	7% 19% 7% 12% 5% 4 4 3 4 4 30%	1730
March	1st to 10th	Day	6% 23% 7% 9% 4 3 4 2 3 4 35%	4920
	11th to 20th	Day	6% 12% 7% 9% 4 3 4 3 5% 6% 40%	5110
	21st to end	Day	11% 22% 5% 10% 5% 4 4 3 5% 5% 27%	5607
April	1st to 10th	Day	12% 13% 4 8% 5% 3 4 4 5% 6% 36%	2336
	11th to 20th	Day	10% 13% 3 8% 5% 4 4 3 5% 6% 39%	2675
	21st to end	Day	10% 12% 3 7% 5% 4 4 3 6% 7% 40%	2730
May	1st to 10th	Day	6% 9% 2 5% 4 3 4 4 5% 7% 49%	7626
	11th to 20th	Day	7% 10% 3 7% 3 4 4 3 5% 7% 47%	7596
	21st to end	Day	6% 4 2 6% 4 4 5% 4 6% 8% 52%	8370
June	1st to 10th	Day	6% 5% 2 5% 4 3 4 4 6% 6% 56%	2924
	11th to 20th	Day	7% 4 2 4 3 3 3 3 4 7% 60%	2974
	21st to end	Day	4 3 1 4 3 2 3 3 4 5% 70%	3079
July	1st to 10th	Day	2 2 1 3 2 2 3 3 5% 6% 72%	7996
	11th to 20th	Day	2 2 1 3 2 3 3 3 6% 8% 65%	7650
	21st to end	Day	3 2 1 3 3 3 3 3 5% 7% 68%	8304
August	1st to 10th	Day	3 2 1 4 3 2 3 2 3 5% 71%	5909
	11th to 20th	Day	2 2 1 3 2 3 3 3 5% 5% 71%	5851
	21st to end	Day	4 3 1 4 3 3 5% 4 5% 6% 62%	6437
September	1st to 10th	Day	4 3 1 3 2 2 3 3 4 5% 69%	2265
	11th to 20th	Day	5% 4 1 5% 3 3 3 3 4 5% 63%	2200
	21st to end	Day	7% 4 1 3 3 2 3 3 4 5% 67%	2200
October	1st to 10th	Day	7% 4 2 4 3 2 3 3 3 4 65%	3435
	11th to 20th	Day	9% 6% 2 6% 3 3 3 3 5% 5% 56%	3250
	21st to end	Day	6% 9% 2 5% 3 3 3 3 4 6% 55%	3491
November	1st to 10th	Day	11% 11% 3 7% 3 4 3 4 5% 6% 43%	1854
	11th to 20th	Day	14% 12% 3 5% 4 3 3 3 5% 8% 40%	1890
	21st to end	Day	9% 14% 5% 7% 4 4 4 3 5% 6% 40%	1685
December	1st to 10th	Day	6% 9% 3 6% 5% 4 3 3 3 5% 53%	2700
	11th to 20th	Day	9% 13% 6% 11% 6% 5% 4 4 5% 7% 29%	3106
	21st to end	Day	9% 18% 7% 10% 5% 5% 5% 4 5% 5% 27%	4393
January	1st to 10th	Night	9% 18% 6% 10% 5% 4 4 3 5% 5% 32%	7605
	11th to 20th	Night	6% 14% 3 9% 4 3 3 3 4 6% 45%	7650
	21st to end	Night	5% 12% 4 7% 4 4 3 4 4 5% 48%	8370
February	1st to 10th	Night	12% 17% 4 9% 5% 4 4 4 4 5% 33%	2730
	11th to 20th	Night	10% 15% 4 10% 5% 3 4 3 4 5% 38%	2598
	21st to end	Night	7% 16% 5% 11% 5% 4 3 4 4 6% 35%	2076
March	1st to 10th	Night	11% 18% 5% 7% 4 4 4 4 4 4 37%	5192
	11th to 20th	Night	7% 12% 3 8% 4 4 5% 4 7% 7% 39%	5110
	21st to end	Night	10% 15% 4 8% 5% 4 4 3 5% 5% 37%	5610
April	1st to 10th	Night	12% 13% 3 6% 4 3 3 3 5% 5% 42%	2284
	11th to 20th	Night	10% 11% 4 7% 4 4 3 3 5% 6% 44%	1890
	21st to end	Night	10% 9% 3 7% 4 4 4 3 5% 6% 46%	1890
May	1st to 10th	Night	7% 7% 2 5% 4 4 4 3 5% 7% 52%	5321
	11th to 20th	Night	7% 5% 2 5% 3 3 3 3 5% 6% 57%	5296
	21st to end	Night	8% 5% 2 6% 4 4 4 4 5% 7% 50%	5837
June	1st to 10th	Night	6% 4 2 4 4 4 3 4 6% 7% 55%	1691
	11th to 20th	Night	7% 3 1 4 3 3 3 3 4 6% 63%	1635
	21st to end	Night	4 2 1 3 3 3 2 3 4 6% 68%	1532
July	1st to 10th	Night	3 4 2 5% 3 3 4 3 5% 6% 63%	4954
	11th to 20th	Night	2 3 2 5% 4 4 5% 4 6% 8% 57%	5340
	21st to end	Night	3 3 1 6% 4 4 4 4 6% 8% 58%	5805
August	1st to 10th	Night	3 2 1 4 4 3 4 3 5% 7% 63%	4123
	11th to 20th	Night	3 3 2 5% 4 4 4 3 5% 5% 61%	4087
	21st to end	Night	4 3 2 6% 4 5% 4 3 5% 5% 59%	4526
September	1st to 10th	Night	5% 2 1 4 3 3 3 3 4 4 67%	2130
	11th to 20th	Night	7% 4 2 4 2 3 3 2 4 5% 64%	2200
	21st to end	Night	7% 3 1 4 3 2 2 2 3 4 68%	2200
October	1st to 10th	Night	6% 4 1 3 2 2 2 2 3 4 70%	3758
	11th to 20th	Night	9% 7% 3 5% 3 3 3 3 4 4 56%	3898
	21st to end	Night	7% 7% 2 5% 4 3 4 3 5% 7% 52%	4304
November	1st to 10th	Night	11% 10% 2 5% 4 4 3 3 5% 6% 47%	2665
	11th to 20th	Night	10% 8% 3 6% 5% 4 5% 3 6% 7% 43%	2730
	21st to end	Night	8% 12% 3 7% 5% 4 4 3 5% 5% 45%	2909
December	1st to 10th	Night	6% 8% 3 7% 4 4 3 3 4 5% 53%	4710
	11th to 20th	Night	11% 13% 4 8% 5% 4 4 4 5% 6% 38%	5321
	21st to end	Night	11% 15% 5% 11% 5% 4 5% 4 5% 6% 29%	6867

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	58% 7% 14% 14% 7% 1	5321
	11th to 20th	Day	42% 4 13% 25% 11% 5%	5340
	21st to end	Day	39% 6% 15% 23% 15% 2	5844
February	1st to 10th	Day	55% 6% 15% 14% 9% 1	1890
	11th to 20th	Day	57% 6% 13% 15% 9% 1	1916
	21st to end	Day	55% 6% 11% 17% 9% 2	1730
March	1st to 10th	Day	53% 4 8% 22% 9% 4	4920
	11th to 20th	Day	41% 6% 9% 30% 13% 1	5110
	21st to end	Day	58% 6% 13% 18% 5% 1	5607
April	1st to 10th	Day	46% 6% 12% 20% 13% 3	2336
	11th to 20th	Day	44% 7% 9% 21% 18% 2	2678
	21st to end	Day	41% 5% 10% 25% 18% 1	2730
May	1st to 10th	Day	30% 6% 9% 24% 26% 5%	7626
	11th to 20th	Day	34% 4 8% 22% 27% 6%	7599
	21st to end	Day	27% 5% 8% 26% 30% 4	8371
June	1st to 10th	Day	25% 5% 10% 22% 32% 6%	2924
	11th to 20th	Day	24% 3 7% 17% 30% 19%	2974
	21st to end	Day	17% 2 5% 12% 33% 32%	3079
July	1st to 10th	Day	14% 2 4 7% 20% 53%	7931
	11th to 20th	Day	15% 3 7% 12% 27% 36%	7581
	21st to end	Day	16% 2 6% 11% 29% 35%	8120
August	1st to 10th	Day	19% 2 5% 15% 29% 31%	4338
	11th to 20th	Day	18% 3 6% 14% 35% 24%	4250
	21st to end	Day	14% 3 5% 15% 35% 28%	4644
September	1st to 10th	Day	16% 3 7% 17% 30% 27%	2265
	11th to 20th	Day	21% 4 8% 16% 34% 17%	2200
	21st to end	Day	20% 4 7% 22% 36% 12%	2200
October	1st to 10th	Day	23% 3 5% 16% 33% 19%	3435
	11th to 20th	Day	29% 4 7% 28% 25% 7%	3250
	21st to end	Day	30% 4 10% 34% 19% 2	3491
November	1st to 10th	Day	41% 6% 12% 22% 18% 1	1854
	11th to 20th	Day	42% 5% 16% 24% 13%	1890
	21st to end	Day	43% 5% 14% 23% 14% 1	1685
December	1st to 10th	Day	34% 6% 12% 37% 11% 1	2700
	11th to 20th	Day	51% 6% 15% 21% 6% 1	3104
	21st to end	Day	56% 6% 11% 18% 9% 1	4393
January	1st to 10th	Night	53% 6% 14% 17% 10% 1	7605
	11th to 20th	Night	40% 5% 12% 31% 11% 2	7650
	21st to end	Night	36% 6% 14% 22% 21% 2	8370
February	1st to 10th	Night	52% 6% 14% 19% 8% 1	2730
	11th to 20th	Night	49% 5% 10% 21% 14% 1	2599
	21st to end	Night	49% 6% 11% 22% 11% 3	2076
March	1st to 10th	Night	49% 4 9% 21% 12% 5%	5192
	11th to 20th	Night	40% 5% 12% 26% 16% 1	5110
	21st to end	Night	47% 5% 17% 21% 10% 1	5610
April	1st to 10th	Night	42% 5% 12% 22% 15% 5%	2284
	11th to 20th	Night	40% 5% 10% 22% 21% 2	1890
	21st to end	Night	38% 4 11% 25% 20% 2	1890
May	1st to 10th	Night	29% 4 11% 22% 30% 4	5319
	11th to 20th	Night	26% 3 8% 22% 32% 9%	5297
	21st to end	Night	30% 4 8% 23% 34% 2	5838
June	1st to 10th	Night	25% 5% 11% 20% 31% 8%	1691
	11th to 20th	Night	22% 3 6% 20% 30% 20%	1635
	21st to end	Night	18% 2 4 13% 30% 32%	1532
July	1st to 10th	Night	21% 1 5% 7% 17% 48%	4911
	11th to 20th	Night	23% 2 7% 9% 23% 36%	5286
	21st to end	Night	23% 3 6% 11% 25% 32%	5677
August	1st to 10th	Night	22% 3 6% 10% 28% 31%	3018
	11th to 20th	Night	25% 3 7% 12% 26% 26%	2964
	21st to end	Night	18% 3 6% 8% 28% 37%	3262
September	1st to 10th	Night	20% 3 6% 15% 24% 32%	2130
	11th to 20th	Night	23% 3 6% 15% 31% 21%	2200
	21st to end	Night	21% 3 6% 18% 36% 17%	2200
October	1st to 10th	Night	20% 2 6% 16% 37% 19%	3758
	11th to 20th	Night	31% 2 5% 28% 26% 8%	3898
	21st to end	Night	30% 3 9% 33% 21% 3	4304
November	1st to 10th	Night	36% 5% 11% 24% 21% 4	2665
	11th to 20th	Night	38% 5% 14% 26% 15% 2	2730
	21st to end	Night	40% 4 12% 28% 13% 3	2909
December	1st to 10th	Night	32% 4 11% 35% 16% 2	4710
	11th to 20th	Night	45% 7% 20% 22% 7%	5322
	21st to end	Night	53% 7% 13% 16% 10%	6867

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	29% 13% 25% 21% 10% 2	330
	11th to 20th	Day	16% 14% 31% 26% 12% 2	330
	21st to end	Day	15% 13% 29% 33% 8% 2	363
February	1st to 10th	Day	28% 15% 31% 19% 5% 2	330
	11th to 20th	Day	23% 16% 38% 17% 6% 1	392
	21st to end	Day	19% 21% 37% 18% 4 1	446
March	1st to 10th	Day	23% 19% 30% 21% 5% 1	540
	11th to 20th	Day	20% 19% 32% 21% 7% 1	540
	21st to end	Day	27% 18% 34% 16% 4	594
April	1st to 10th	Day	19% 19% 32% 20% 9% 1	540
	11th to 20th	Day	22% 24% 31% 17% 5% 1	532
	21st to end	Day	20% 20% 30% 20% 8% 2	540
May	1st to 10th	Day	18% 19% 32% 22% 10%	543
	11th to 20th	Day	18% 18% 28% 25% 9% 2	568
	21st to end	Day	15% 14% 30% 24% 13% 3	617
June	1st to 10th	Day	6% 14% 26% 33% 16% 4	764
	11th to 20th	Day	11% 13% 33% 27% 14% 2	780
	21st to end	Day	8% 10% 35% 28% 16% 3	709
July	1st to 10th	Day	4 9% 40% 33% 11% 3	566
	11th to 20th	Day	4 6% 37% 35% 13% 5%	564
	21st to end	Day	6% 5% 34% 38% 13% 4	619
August	1st to 10th	Day	8% 6% 35% 33% 13% 5%	567
	11th to 20th	Day	5% 8% 31% 38% 13% 5%	534
	21st to end	Day	6% 7% 29% 36% 16% 5%	583
September	1st to 10th	Day	3 12% 29% 34% 16% 7%	530
	11th to 20th	Day	9% 13% 28% 31% 14% 5%	530
	21st to end	Day	9% 12% 30% 29% 17% 3	530
October	1st to 10th	Day	15% 12% 27% 26% 17% 4	430
	11th to 20th	Day	13% 15% 27% 22% 19% 4	330
	21st to end	Day	16% 12% 31% 28% 11% 1	363
November	1st to 10th	Day	22% 15% 22% 24% 11% 5%	330
	11th to 20th	Day	17% 14% 29% 28% 10% 2	330
	21st to end	Day	14% 15% 24% 28% 17% 3	330
December	1st to 10th	Day	16% 13% 30% 23% 13% 6%	330
	11th to 20th	Day	22% 10% 29% 28% 8% 2	330
	21st to end	Day	30% 13% 24% 21% 9% 3	363
January	1st to 10th	Night	21% 7% 19% 34% 17% 3	840
	11th to 20th	Night	18% 5% 20% 37% 16% 4	840
	21st to end	Night	18% 6% 20% 38% 14% 3	924
February	1st to 10th	Night	22% 7% 23% 36% 11% 2	840
	11th to 20th	Night	16% 7% 27% 35% 13% 2	824
	21st to end	Night	13% 9% 30% 34% 14% 1	692
March	1st to 10th	Night	21% 9% 23% 33% 11% 3	840
	11th to 20th	Night	15% 8% 22% 39% 15% 2	840
	21st to end	Night	20% 9% 22% 35% 14% 1	924
April	1st to 10th	Night	19% 9% 22% 33% 15% 1	814
	11th to 20th	Night	15% 11% 25% 34% 13% 2	623
	21st to end	Night	18% 6% 20% 37% 18% 2	630
May	1st to 10th	Night	15% 8% 24% 33% 19% 1	630
	11th to 20th	Night	14% 6% 17% 34% 26% 3	621
	21st to end	Night	14% 7% 16% 36% 24% 4	683
June	1st to 10th	Night	8% 7% 16% 38% 28% 2	630
	11th to 20th	Night	10% 5% 22% 39% 22% 1	585
	21st to end	Night	7% 4 18% 38% 29% 5%	420
July	1st to 10th	Night	7% 4 14% 37% 34% 4	478
	11th to 20th	Night	6% 3 11% 45% 33% 2	612
	21st to end	Night	5% 1 8% 44% 39% 3	690
August	1st to 10th	Night	6% 2 11% 45% 34% 1	627
	11th to 20th	Night	5% 1 14% 43% 34% 3	606
	21st to end	Night	7% 4 11% 39% 35% 4	660
September	1st to 10th	Night	6% 4 12% 39% 35% 4	730
	11th to 20th	Night	9% 5% 13% 38% 28% 7%	800
	21st to end	Night	9% 5% 16% 32% 29% 9%	800
October	1st to 10th	Night	13% 6% 14% 38% 26% 4	800
	11th to 20th	Night	16% 5% 16% 33% 27% 4	800
	21st to end	Night	13% 4 18% 36% 25% 4	880
November	1st to 10th	Night	16% 6% 15% 38% 21% 4	820
	11th to 20th	Night	16% 5% 22% 39% 15% 3	840
	21st to end	Night	15% 8% 20% 34% 20% 4	1019
December	1st to 10th	Night	16% 7% 24% 36% 15% 2	1050
	11th to 20th	Night	21% 8% 24% 34% 11% 2	1050
	21st to end	Night	26% 9% 23% 31% 9% 2	1037

Page generated at 2026-08-12 01:37:19. Version ac07

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