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 2025-04-11.

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	7% 10% 3 7% 4 3 4 3 4 6% 49%	117961
	Night	8% 10% 3 7% 4 3 4 3 5% 6% 48%	119245
Transparency	Day	35% 5% 9% 19% 20% 12%	117724
	Night	37% 5% 10% 20% 19% 9%	119071
Seeing	Day	14% 13% 30% 27% 12% 3	15737
	Night	14% 6% 19% 36% 21% 3	25813

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	6% 22% 7% 11% 5% 3 4 4 5% 5% 28%	4098
	11th to 20th	Day	6% 16% 7% 13% 6% 5% 4 2 3 4 34%	4100
	21st to end	Day	6% 16% 6% 9% 4 3 3 3 3 5% 43%	4510
February	1st to 10th	Day	14% 19% 5% 10% 4 4 4 3 5% 5% 28%	1800
	11th to 20th	Day	10% 21% 6% 10% 6% 3 4 2 3 4 29%	1814
	21st to end	Day	6% 19% 8% 13% 5% 4 4 3 4 4 29%	1650
March	1st to 10th	Day	6% 23% 7% 9% 4 3 4 2 3 4 35%	4814
	11th to 20th	Day	6% 12% 7% 9% 4 4 5% 3 5% 6% 40%	5000
	21st to end	Day	11% 23% 5% 10% 5% 4 4 3 4 4 27%	5486
April	1st to 10th	Day	12% 13% 4 8% 5% 3 4 3 5% 6% 36%	2225
	11th to 20th	Day	11% 14% 3 8% 5% 4 4 3 5% 6% 39%	2418
	21st to end	Day	11% 12% 3 6% 4 3 3 3 6% 7% 41%	2470
May	1st to 10th	Day	9% 16% 3 7% 5% 4 4 4 5% 7% 36%	4110
	11th to 20th	Day	8% 5% 2 5% 3 3 4 3 6% 8% 54%	4071
	21st to end	Day	9% 6% 2 6% 4 4 5% 4 5% 7% 48%	4477
June	1st to 10th	Day	6% 5% 2 5% 4 4 4 4 6% 7% 54%	2646
	11th to 20th	Day	8% 4 2 4 3 3 3 3 5% 7% 58%	2690
	21st to end	Day	4 2 1 3 3 2 3 3 4 4 71%	2786
July	1st to 10th	Day	3 2 1 2 2 2 2 2 4 4 77%	4301
	11th to 20th	Day	3 2 1 3 2 3 3 3 6% 8% 65%	4110
	21st to end	Day	4 2 1 3 3 3 3 3 5% 7% 66%	4454
August	1st to 10th	Day	4 3 2 4 3 3 3 2 4 6% 66%	4092
	11th to 20th	Day	3 2 1 4 3 3 4 3 5% 5% 67%	4028
	21st to end	Day	3 2 1 2 2 2 3 3 4 5% 73%	4503
September	1st to 10th	Day	4 3 1 3 2 2 3 3 4 5% 70%	2152
	11th to 20th	Day	5% 3 1 5% 3 3 3 3 4 5% 64%	2090
	21st to end	Day	7% 4 1 3 3 2 2 3 4 4 67%	2090
October	1st to 10th	Day	7% 4 2 4 3 2 3 3 3 4 65%	3330
	11th to 20th	Day	9% 6% 2 6% 3 3 3 3 5% 5% 56%	3150
	21st to end	Day	7% 9% 3 5% 4 3 3 3 4 6% 55%	3383
November	1st to 10th	Day	12% 12% 3 8% 3 4 3 4 5% 5% 42%	1764
	11th to 20th	Day	14% 12% 3 4 4 3 3 3 6% 8% 41%	1800
	21st to end	Day	9% 15% 5% 7% 3 4 4 3 5% 6% 40%	1605
December	1st to 10th	Day	7% 8% 3 6% 5% 3 3 3 3 5% 54%	2620
	11th to 20th	Day	9% 13% 6% 12% 6% 5% 4 4 5% 7% 29%	3026
	21st to end	Day	9% 18% 7% 10% 5% 5% 5% 4 5% 5% 27%	4298
January	1st to 10th	Night	7% 16% 6% 11% 5% 4 3 3 5% 5% 35%	5867
	11th to 20th	Night	7% 18% 4 12% 5% 4 4 3 4 6% 32%	5880
	21st to end	Night	6% 15% 4 8% 3 3 3 3 4 4 46%	6468
February	1st to 10th	Night	13% 18% 4 9% 5% 3 4 3 4 5% 32%	2600
	11th to 20th	Night	10% 15% 4 10% 5% 3 4 3 4 5% 39%	2471
	21st to end	Night	6% 17% 5% 11% 5% 4 3 4 4 6% 34%	1980
March	1st to 10th	Night	11% 18% 5% 7% 4 4 4 4 4 4 37%	5078
	11th to 20th	Night	7% 12% 3 9% 4 4 5% 4 7% 7% 38%	5000
	21st to end	Night	10% 15% 4 8% 4 4 5% 3 5% 5% 37%	5489
April	1st to 10th	Night	12% 14% 3 6% 4 3 3 3 5% 5% 42%	2175
	11th to 20th	Night	10% 11% 4 7% 4 4 3 3 4 5% 44%	1713
	21st to end	Night	11% 9% 3 6% 4 4 4 3 5% 6% 47%	1710
May	1st to 10th	Night	12% 12% 3 6% 5% 4 5% 3 4 6% 39%	2860
	11th to 20th	Night	9% 3 2 4 3 3 3 3 5% 6% 59%	2834
	21st to end	Night	12% 5% 2 6% 5% 4 3 3 5% 6% 50%	3110
June	1st to 10th	Night	7% 4 2 5% 4 4 4 4 7% 7% 54%	1530
	11th to 20th	Night	8% 3 1 5% 3 3 3 3 5% 6% 61%	1479
	21st to end	Night	4 2 1 3 3 3 2 3 3 7% 69%	1386
July	1st to 10th	Night	3 2 1 3 2 2 3 2 4 4 74%	2656
	11th to 20th	Night	3 3 1 5% 4 3 4 4 5% 8% 59%	2860
	21st to end	Night	3 3 1 5% 3 3 4 4 5% 7% 61%	3109
August	1st to 10th	Night	4 3 1 5% 4 4 5% 3 5% 7% 60%	2847
	11th to 20th	Night	3 4 2 6% 4 4 4 3 5% 6% 60%	2811
	21st to end	Night	3 2 1 3 3 3 3 3 4 5% 70%	3163
September	1st to 10th	Night	5% 2 1 4 3 3 3 3 4 4 68%	2023
	11th to 20th	Night	7% 4 2 3 2 3 3 2 4 5% 65%	2090
	21st to end	Night	7% 3 1 3 2 2 2 2 3 4 70%	2090
October	1st to 10th	Night	6% 3 1 3 2 2 2 2 3 4 70%	3643
	11th to 20th	Night	8% 7% 2 5% 3 3 3 3 4 4 56%	3778
	21st to end	Night	7% 7% 2 5% 4 3 4 4 5% 7% 52%	4170
November	1st to 10th	Night	11% 10% 2 5% 3 4 3 3 5% 6% 47%	2535
	11th to 20th	Night	11% 8% 3 6% 5% 3 4 3 6% 7% 44%	2600
	21st to end	Night	8% 12% 3 7% 5% 4 4 3 4 5% 44%	2770
December	1st to 10th	Night	6% 8% 3 7% 4 4 3 3 4 5% 54%	4570
	11th to 20th	Night	11% 13% 4 8% 5% 4 4 4 5% 6% 38%	5181
	21st to end	Night	10% 15% 5% 11% 5% 4 5% 4 5% 6% 29%	6719

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	56% 6% 13% 15% 8% 1	4099
	11th to 20th	Day	53% 6% 14% 16% 8% 3	4100
	21st to end	Day	44% 6% 13% 20% 16% 1	4510
February	1st to 10th	Day	57% 6% 15% 13% 9% 1	1800
	11th to 20th	Day	56% 6% 13% 15% 9% 1	1823
	21st to end	Day	56% 6% 11% 16% 9% 2	1650
March	1st to 10th	Day	53% 4 8% 22% 9% 4	4814
	11th to 20th	Day	42% 6% 9% 30% 12% 1	5000
	21st to end	Day	58% 6% 13% 18% 4 1	5486
April	1st to 10th	Day	47% 6% 12% 19% 13% 3	2225
	11th to 20th	Day	45% 7% 9% 21% 17% 2	2421
	21st to end	Day	41% 5% 11% 24% 18% 1	2470
May	1st to 10th	Day	42% 7% 11% 19% 17% 4	4110
	11th to 20th	Day	25% 5% 10% 30% 24% 6%	4074
	21st to end	Day	30% 7% 11% 24% 25% 2	4477
June	1st to 10th	Day	25% 6% 11% 23% 29% 6%	2646
	11th to 20th	Day	26% 4 7% 18% 28% 18%	2690
	21st to end	Day	16% 2 5% 12% 31% 34%	2786
July	1st to 10th	Day	12% 2 4 9% 14% 60%	4235
	11th to 20th	Day	15% 2 5% 9% 26% 42%	4041
	21st to end	Day	16% 3 6% 9% 31% 35%	4314
August	1st to 10th	Day	19% 2 6% 15% 29% 29%	4078
	11th to 20th	Day	18% 3 6% 14% 35% 24%	4067
	21st to end	Day	13% 3 5% 15% 36% 29%	4502
September	1st to 10th	Day	16% 3 7% 16% 30% 28%	2152
	11th to 20th	Day	21% 5% 8% 16% 33% 17%	2090
	21st to end	Day	20% 4 7% 21% 36% 12%	2090
October	1st to 10th	Day	23% 3 5% 16% 33% 20%	3330
	11th to 20th	Day	29% 4 7% 28% 25% 8%	3150
	21st to end	Day	31% 4 11% 33% 19% 2	3383
November	1st to 10th	Day	42% 6% 12% 21% 18% 1	1764
	11th to 20th	Day	41% 5% 16% 25% 14%	1800
	21st to end	Day	44% 5% 14% 22% 14% 1	1605
December	1st to 10th	Day	33% 5% 12% 38% 11% 1	2620
	11th to 20th	Day	52% 6% 15% 21% 6%	3024
	21st to end	Day	56% 6% 11% 17% 9% 1	4298
January	1st to 10th	Night	51% 6% 11% 19% 12% 1	5867
	11th to 20th	Night	52% 6% 12% 22% 7% 1	5880
	21st to end	Night	41% 6% 12% 22% 18% 1	6468
February	1st to 10th	Night	53% 7% 13% 18% 8% 1	2600
	11th to 20th	Night	48% 5% 11% 21% 15% 2	2472
	21st to end	Night	50% 6% 11% 20% 11% 3	1980
March	1st to 10th	Night	49% 4 9% 21% 12% 5%	5078
	11th to 20th	Night	40% 5% 12% 26% 16% 1	5000
	21st to end	Night	47% 5% 17% 21% 9% 1	5489
April	1st to 10th	Night	43% 5% 12% 21% 14% 5%	2175
	11th to 20th	Night	41% 6% 10% 22% 20% 2	1713
	21st to end	Night	37% 5% 11% 25% 20% 2	1710
May	1st to 10th	Night	42% 5% 12% 19% 19% 3	2860
	11th to 20th	Night	24% 5% 9% 29% 25% 7%	2835
	21st to end	Night	33% 5% 10% 23% 28% 1	3110
June	1st to 10th	Night	26% 6% 11% 21% 30% 6%	1530
	11th to 20th	Night	23% 3 7% 21% 29% 17%	1479
	21st to end	Night	17% 2 4 13% 29% 35%	1386
July	1st to 10th	Night	13% 2 5% 7% 15% 58%	2613
	11th to 20th	Night	22% 2 5% 8% 28% 34%	2806
	21st to end	Night	21% 3 6% 9% 28% 32%	3011
August	1st to 10th	Night	23% 3 6% 10% 29% 29%	2838
	11th to 20th	Night	25% 3 7% 13% 26% 26%	2838
	21st to end	Night	16% 3 6% 8% 29% 37%	3163
September	1st to 10th	Night	20% 3 6% 14% 24% 33%	2023
	11th to 20th	Night	22% 3 6% 16% 31% 22%	2090
	21st to end	Night	20% 3 6% 18% 36% 18%	2090
October	1st to 10th	Night	19% 2 6% 16% 37% 19%	3643
	11th to 20th	Night	30% 2 5% 28% 27% 8%	3778
	21st to end	Night	30% 3 9% 34% 21% 3	4170
November	1st to 10th	Night	37% 5% 11% 24% 20% 4	2535
	11th to 20th	Night	38% 5% 14% 26% 15% 2	2600
	21st to end	Night	41% 4 12% 27% 13% 3	2770
December	1st to 10th	Night	32% 4 11% 35% 16% 2	4570
	11th to 20th	Night	45% 7% 20% 21% 7%	5182
	21st to end	Night	53% 7% 13% 16% 10%	6719

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	28% 13% 25% 22% 11% 2	300
	11th to 20th	Day	17% 14% 31% 25% 11% 1	300
	21st to end	Day	16% 13% 26% 34% 8% 2	330
February	1st to 10th	Day	30% 15% 31% 19% 3 1	300
	11th to 20th	Day	22% 16% 38% 17% 6% 1	359
	21st to end	Day	18% 21% 37% 18% 5% 1	414
March	1st to 10th	Day	22% 20% 30% 22% 5% 1	500
	11th to 20th	Day	19% 19% 33% 22% 7% 1	500
	21st to end	Day	29% 16% 35% 17% 3	550
April	1st to 10th	Day	19% 20% 33% 18% 9% 1	500
	11th to 20th	Day	22% 23% 30% 18% 5% 2	453
	21st to end	Day	20% 20% 28% 21% 9% 2	460
May	1st to 10th	Day	19% 19% 32% 21% 9%	463
	11th to 20th	Day	16% 16% 28% 27% 10% 2	488
	21st to end	Day	15% 13% 30% 24% 14% 3	529
June	1st to 10th	Day	5% 13% 26% 34% 17% 4	666
	11th to 20th	Day	12% 13% 30% 28% 15% 2	680
	21st to end	Day	6% 9% 34% 30% 18% 3	616
July	1st to 10th	Day	4 9% 37% 34% 12% 3	486
	11th to 20th	Day	4 6% 37% 36% 13% 4	484
	21st to end	Day	5% 4 33% 40% 15% 4	531
August	1st to 10th	Day	8% 6% 32% 34% 14% 5%	487
	11th to 20th	Day	5% 8% 28% 39% 14% 5%	477
	21st to end	Day	6% 8% 28% 37% 17% 5%	539
September	1st to 10th	Day	3 11% 28% 34% 17% 6%	490
	11th to 20th	Day	9% 12% 28% 32% 14% 5%	490
	21st to end	Day	9% 11% 29% 30% 18% 3	490
October	1st to 10th	Day	13% 12% 26% 27% 17% 5%	395
	11th to 20th	Day	11% 14% 27% 23% 21% 4	300
	21st to end	Day	15% 13% 31% 29% 10% 1	330
November	1st to 10th	Day	23% 15% 21% 25% 11% 5%	300
	11th to 20th	Day	16% 14% 30% 28% 9% 3	300
	21st to end	Day	15% 13% 24% 28% 17% 3	300
December	1st to 10th	Day	15% 10% 30% 24% 14% 7%	300
	11th to 20th	Day	21% 11% 29% 30% 6% 2	300
	21st to end	Day	28% 14% 26% 22% 7% 3	330
January	1st to 10th	Night	20% 7% 18% 34% 18% 3	800
	11th to 20th	Night	19% 6% 20% 36% 16% 4	800
	21st to end	Night	18% 6% 21% 36% 15% 4	880
February	1st to 10th	Night	23% 7% 24% 35% 11% 2	800
	11th to 20th	Night	15% 7% 27% 35% 13% 2	784
	21st to end	Night	12% 9% 29% 34% 14% 1	660
March	1st to 10th	Night	21% 9% 22% 34% 11% 3	800
	11th to 20th	Night	15% 7% 21% 39% 15% 2	800
	21st to end	Night	21% 9% 20% 34% 14% 1	880
April	1st to 10th	Night	20% 8% 23% 34% 15% 1	775
	11th to 20th	Night	15% 12% 24% 33% 14% 2	565
	21st to end	Night	17% 5% 19% 37% 18% 3	570
May	1st to 10th	Night	16% 8% 25% 32% 18% 1	570
	11th to 20th	Night	14% 5% 17% 33% 27% 3	561
	21st to end	Night	14% 6% 16% 36% 24% 4	617
June	1st to 10th	Night	9% 6% 16% 38% 29% 2	570
	11th to 20th	Night	10% 6% 22% 38% 22% 2	529
	21st to end	Night	6% 3 18% 37% 30% 5%	380
July	1st to 10th	Night	7% 4 14% 35% 35% 4	431
	11th to 20th	Night	7% 3 11% 44% 33% 2	552
	21st to end	Night	5% 1 7% 43% 40% 3	624
August	1st to 10th	Night	7% 2 11% 44% 35% 2	567
	11th to 20th	Night	4 1 14% 43% 36% 3	564
	21st to end	Night	7% 4 12% 39% 34% 5%	627
September	1st to 10th	Night	6% 4 12% 40% 34% 4	693
	11th to 20th	Night	9% 5% 12% 38% 28% 8%	760
	21st to end	Night	9% 5% 16% 32% 29% 9%	760
October	1st to 10th	Night	13% 6% 14% 38% 26% 4	760
	11th to 20th	Night	15% 4 15% 34% 28% 4	760
	21st to end	Night	12% 5% 19% 36% 24% 4	836
November	1st to 10th	Night	16% 6% 15% 38% 21% 4	780
	11th to 20th	Night	16% 5% 22% 39% 16% 3	800
	21st to end	Night	15% 8% 20% 34% 20% 4	970
December	1st to 10th	Night	16% 7% 23% 37% 15% 2	1000
	11th to 20th	Night	21% 8% 24% 34% 11% 2	1000
	21st to end	Night	24% 9% 24% 32% 9% 2	988

Page generated at 2025-04-08 07:17:30. Version ac07

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