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Show HN: The best time to visit any city

395 points by ignostic ↗ HN
I wanted to build a tool to help people decide when and where to travel. As I started building, I realized that "when" and "where" need separate treatment to be most useful. The map tool handles "where" best:

https://championtraveler.com/travel-weather-map/

Clicking through each week would be frustrating for those who know where they want to travel but not when. For these people I built "best time to travel" pages using the same data.

https://championtraveler.com/best-time-to-travel/

My hope is this site will help travelers plan.

This data is taken from the National and Atmospheric Administration's global summaries of the day (NOOA's GSoD). I used an SQL database to crunch the numbers into monthly and weekly averages by station. For the "best time" pages I used and calculated several more variables. I then imported the data into Tableau and added the filters you see on the map. I also used data from the State Department regarding travel advisories.

Would love your thoughts!

The whole buildout was a solo project, but I owe Ryan Whitacker a big "thank you" for his guidance. He built a similar tool on his site (https://decisiondata.org/the-best-time-to-visit-anywhere/) in April, and was generous to offer me guidance for expanding upon his idea.

Known issues:

* I am aware that the map is bad on mobile, so my next step is to improve the mobile experience.

121 comments

[ 3.5 ms ] story [ 178 ms ] thread
sharkweek
This is great - I think the search functionality could be improved a bit (a lot of results following the one I was looking for that didn't seem related, but the right one did show up first).

I wonder if there would be a benefit of a "community" element as well, as in allowing comments on the pages, to give locals the opportunity to chime in with their advice.

ignostic
Thanks! I agree on the search functionality. Right now this is just a WordPress search, but it would probably be wise to use Google's location API to help find the right place or the closest place to it. I have no experience here, but I can work on adding it.

Will have to think about the community option as well. I'm not sure what the best implementation would be, but it's a good idea. Thanks for the positive response and constructive feedback!

Malic
Love the idea, but yes, the search needs some work. For example, the search engine doesn't get "St. Louis, MO" right at all.

Iterate and carry on!

snegu
I'd be curious to know why so many search functions have trouble with St. Louis. I was recently trying to book a flight there, and often had to use the airport code to have it show up!
wyldfire
> Tourism graph is based on Google searches for services used by tourists relative to the rest of the year.

That's a pretty clever way to go about it. I hope/suppose that the sampling bias isn't correlated with time-of-year somehow.

bawana
It's actually inaccurate. People search BEFORE they go. In fact, I can tell you the busiest tourism month in Greece is August. I've been there dozens of times and June is actually a pleasant (tho cool-ish) time to visit - no crowds. And the Greeks are still working (trying to make money to spend on their August vacations - when everything shuts down). Perhaps Airline charters would be a more accurate reflection. Altho I do not know where to source that data.
clementangerine
It seems pretty off, though. For example, the page for Iceland says that winter is the peak time, but it's actually pretty dead in the winter with the peak in the summer. Seems like people start planning their summer trips around December (plane tickets for Christmas?). Other places seem shifted up a month or two - the page for Paris has the peak season around May-June, but it's actually more like June-August.

OP, if you want to improve this, could you get some actual tourist data and experiment a bit with which other metrics (various Google searches - something like taxi services might be more accurate to estimate how many people are actually traveling in the country at the time, hotel prices, plane ticket prices, etc) best predict the tourist numbers?

stinos
This is really neat! Only thoughts: it assumes one's definition of 'best' is 'best weather' and that in turn means it matches with what your algorithm decides is most pleasurable (which I think it does a pretty good job at). This is probably ok for most people but e.g. I like to travel to see nature and rare species of plants and whatnot, and that completely changes what 'best' is for me as it makes weather not one of the top things to consider.
ignostic
Thank you! I am very glad others find the algorithm finding the "best times" to be accurate as well. This was definitely the hardest problem to solve as some places have two seasons, some have one, and I'm trying to find the best time on a scale relative to that place.

I'm aware not everyone will be satisfied the "pleasant weather" parameters I used, but I don't think there's another way to give a range quickly. Perhaps I could add some options on those pages. I'm not sure it would be worth the extra clutter and work to catch edge cases, though, as I'll never satisfy everyone's travel preference. Right now those looking for other weather preferences can use the map, but I understand clicking through several weeks is less than ideal. Hopefully the graphs on the page offer a bit more guidance for you.

One question: are you aware of any dataset that would help locate rare species? I can't guarantee I'll use it, but I love having lots of data handy.

efm
I'd prefer not to have an app to find rare species. They're rare for a reason, and that reason is because there are few places the can live, and those places are likely difficult for people to get to. Please don't make it easier for people to get there.
stinos
I'm not sure it would be worth the extra clutter

Not likely. I mean, for like 99% the current parameters are ok, stuff is easy to use, why bother changing it :]

are you aware of any dataset that would help locate rare species

Not directly but there's sites like observation.org, not sure if they have APIs. Be warned though: it's a lot of information because there are so many species so making crawling through that handy and useful would require quite the interface.

MattBlissett
GBIF, https://www.gbif.org/, aggregates biodiversity occurrence data (observations, where specimens held in museums are from, etc).

Everything is available through an open API, although we don't index threat status. Perhaps we should.

Example: Ceratotherium simum, Southern White Rhinoceros [1]. (The threat status shown on the page is taken from an IUCN API.) The distribution data is available either as individual occurrence records [2], or as a summarized map vector tile [3], or a PNG map tile [4]. You would probably want to add a year range filter for recent observations.

You can also download e.g. everything with coordinates and crunch through the data yourself.

You will often find the coordinates have a low accuracy for endangered species, to prevent misuse. I won't comment on whether making such an app is a good idea or not.

(I am a software developer at GBIF.)

[1] https://www.gbif.org/species/2440880

[2] https://api.gbif.org/v1/occurrence/search?has_coordinate=tru...

[3] https://api.gbif.org/v2/map/occurrence/density/0/0/0.mvt?tax...

[4] https://api.gbif.org/v2/map/occurrence/density/0/0/0@1x.png?...

stinos
Wow, thanks for mentioning this. Didn't know it but it looks pretty awesome especially becuase of the combination of all datasets.
pkulak
This seems really off:

https://championtraveler.com/dates/best-time-to-visit-portla...

It's says the daily highs in the summer are low 60s and that the driest months are in the middle of the winter.

ignostic
> It's says the daily highs in the summer are low 60s

Temperature numbers show the average for the week. E.g. the "high" on the dot is not the highest average day, but the average high. I double checked and these look correct. Check out the "heat index" adjusted numbers below for perceived temperatures, as Portland feels significantly warmer due to humidity in the summer.

> the driest months are in the middle of the winter.

I'm confused here. If you're looking at Portland, OR the driest months are shown as being in the summer, so I'm not sure what you're referring to. Did you maybe look at another Portland?

pkulak
Ah, weekly average makes more sense.

As to the second part:

"If dry weather is what you’re after, the months with the lowest chance of precipitation in Portland are November, December, and then February."

slg
I agree. Check Atlanta for example. The note says, "The warmest time of year is generally late June where highs are regularly around 71.6°F (22°C)" [1]. Meanwhile the historic average highs for August range from 86-89°F [2]. The average low in August [3] is almost as high as what this site says is the warmest regular high.

[1] - https://championtraveler.com/dates/best-time-to-visit-atlant...

[2] - https://www.accuweather.com/en/us/atlanta-ga/30303/august-we...

[3] - https://en.wikipedia.org/wiki/Atlanta#Climate

mcjiggerlog
Also looking at it for Madrid:

https://championtraveler.com/dates/best-time-to-visit-madrid...

It's completely wrong. Highs of 22c in August? Try 40c!

If you can fix the data then this will be super useful!

Also, maybe it would be a good idea to let people add their own tips (that people can then vote up/down), because it may be useful to know, for example, that in August in Madrid most bars, restaurants and shops are closed as everyone flees to the coast.

hissworks
Really neat application of the data. I'm the Director of Marketing at a mid-sized destination marketing organization (DMO) represented on your map (Aurora, Illinois -- we're actually a terrific place to visit in winter!). Curious to learn more about the variables used to deploy the "best time" pages and get a sense for where you'd like to take this further.
andyjsantamaria
This is super interesting idea and something I'd reference a lot. The big question I have is what are your factors for deciding the best time to visit? I'd argue setting up the context is really important because weather is a major factor but it isn't the only one. There are times of year that have cultural significance as well as annual events, etc. I like the safety advisory aspect and the population of travelers. It would be interesting to know what types of groups travel there and when. So for instance, I want to go to Hawaii but not there are going to be tons of kids and I'd like to do it cheaply and I don't care about the weather.

Lastly, I don't recommend bucketing NZ under Australia :)

mod
Do you think NZ should be bucketed under Asia instead?
stickydink
Australasia
vacri
Kiwiland is further from mainland Asia than pretty much anywhere else is, excluding the Americas. I'd go for Oceania, and throw Australia in there as well.
ignostic
> what are your factors for deciding the best time to visit?

I used almost exclusively weather data. My scoring process is linked to near the date ranges I provide, so hopefully that is clear.

I would love to make better use of the number of people visiting. I had a really hard time getting additional travel data for what times are busiest, but I did my best with Google data. I'd even be willing to pay for tourist data by week or month, but I don't believe it exists on the scale I'd need it. If I find it, though, I'll be sure to iterate!

> Lastly, I don't recommend bucketing NZ under Australia :)

Good call. I changed the heading to "Australia & Oceania"

icebraining
I doubt there's a single dataset containing tourist occupation across the world, but you can probably find it city by city, although often only in the original language.

For example, there's a report on the rate of occupation of hotels per fortnight in Barcelona, but it's a PDF and it's not even in Spanish (Castellano), but in Catalan, the regional language: https://www.diba.cat/documents/74348/115651101/Informe+Flaix...

netsharc
I wrote earlier that I used a website witb an Instagram heatmap to see places around me in a tourist destination that people took pics, if that website used time as another dimension (not just geo coordinates), it would be a rough approximation of the popularity of destinations per week/month.
andyjsantamaria
Nice. It's true NZ is small but it's worth standing on its own.

Weather is important but it's not the only factor or the most important one for everyone. If there was "One tool to rule them all" for travel I think this could be really powerful. :)

xxXXxx-
Yes! There's a few cities I visit very often but I ONLY visit in the "off season." Everything is much cheaper, things don't sell out, I don't get bothered by stupid events I have no interest in, parking is free or reduced price, I don't have to sit in traffic, and crowds are non-existent. I'd rather avoid crowds than pretty much any other factor other than maybe price.
larrydag
I thought the same thing. My biggest factor is cost of travel and whether its in season or out of season. Then I guess the site would turn into a travelocity or expedia.
fireworks10
http://offpeak.io the project my team has been working on aims to solve this exact problem. We help travelers avoid peak season, and peak dates that are often associated with large business conferences.
ignostic
That's great! May I ask where you're getting your data?
gardnr
The search is really frustrating. Everything I type is not there and then it shows me things that are very far away from what I typed. It may be better to show a list organized by region or show the closest location you do cover to the one that was typed in.
Xeoncross
It seems to be missing all but the largest cities. My guess is that you are manually adding data which would mean higher quality at the cost of general usefulness.
netsharc
I used an Instagram heatmap to find places to visit/look at during a holiday, I would guess if one adds a "time heatmap" one can see which weeks/months are quieter and which are busier.
schoen
I had a great trip with a group of friends to Iceland in mid-winter, which was a time that other people were reluctant to go. It definitely made certain travel activities harder or impossible, but we got to experience lots of great things and many prices were lower. We also saw the spectacular Reykjavík new year's fireworks.

But I'd also appreciate this site's advice is handy because weather in a distant place is so unfamiliar and can have such a big impact on a trip.

Another idea: maybe look through each category in the Köppen classification and figure out what weather factors in such a climate would most affect the quality of someone's visit. For example,

https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classifica...

Then somehow highlight those particular factors for each place. (I don't really know how best to organize this information.)

pidg
"As of 6/22/2017 there are travel warnings for the United Kingdom; exercise a high degree of caution."

I thought this was an error at first, but the .ca travel advice is indeed to be extra careful visiting the UK.

Spain, meanwhile: "Exercise normal security precautions".

Huh.

I guess it's only as good as the data sources :)

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icebraining
Terrorist attacks are not earthquakes. Barring further evidence, there's no reason to believe Spain is any more dangerous today than it was two weeks ago. If anything, it's less, since there's one fewer group planning an attack.

Then again, I recently moved to Brussels and I'm planning an impromptu trip to Barcelona thanks to the falling flight prices, so maybe I'm just suicidal :)

loblollyboy
You made my point better than me. Ppl go to Germany for Oktoberfest, too Vermont for foliage, to Utah for skiing - additionally, these could be reasons to not go to those places at those times.
Eiriksmal
I love your weather summaries. Your formula nails it with this one: https://championtraveler.com/dates/best-time-to-visit-san-di...

Most weather summaries seem to miss that early/mid-September is significantly hotter than the traditionally hot months of July and August for most locations.

https://championtraveler.com/dates/best-time-to-visit-louisv... > When can you find snow in Louisville? Weather stations report a bit of annual snow likely to be deepest around March, especially close to early March. Powder (new snow) is most often falls around November 12th.

Seeing powder forecasts for Louisville, KY cracked me up.

ignostic
Thanks! Most places actually give far more specific date ranges, but San Diego is so temperate just listing the months made more sense.

"Powder" I guess is not the word I should be using in places like this, but the dates are usually accurate in places that get powder at all :)

telotortium
However, there does seem to be a mistake in the precipitation section:

"If dry weather is what you’re after, the months with the lowest chance of precipitation in San Diego are December, February, and then January."

Eiriksmal
Good eye. @ignostic, it's reporting the highest percent chance of precipitation by month, not lowest, in the textual summary of both cities.

"The lowest chance of rain and snow" blurb is correct.

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kristianc
This is a really interesting idea - the kind of tool that you only realize that you've been waiting for when someone shows you it! As someone who likes to travel quite a bit, this will replace a lot of Google searches for me potentially. Your weather summaries will also be great for SEO and are very well optimised.

One bit of feedback I'd give is it'd be worth populating with some "temperate" defaults (i.e. normal average temperature, normal humidity etc.). At the moment it seems like it might take a bit of configuring to get to the information you'd want, when it'd seem like you could take an educated guess.

UI/UX wise I would also make the "date" slider a bit more prominent and maybe have it simply limited to monthly averages (doesn't seem to matter too much if we're talking 2nd or 3rd week of March) for instance.

Otherwise, really love it, and excited to see the ways people are using Tableau for this kind of thing :)

mule76
Pretty cool job.

It would be nice if the user had a few sliders to toggle (heat, humidity, rain, and crowds), rated say 0 to 10 (with 5 meaning don't care), to get around having to select an ideal temperature for everyone. Some people want sun, others want snow, and others don't care about either.

Symbiote
I was surprised with the cities shown on the map -- nothing from Britain or Ireland, only Odense from Scandinavia, yet five places in Moldova and loads more in Ukraine.

Looking at Copenhagen [1], the Celsius graph is maxing out at 10°C -- perhaps it would be neater to show a single graph, with a Fahrenheit scale on the left and Celsius on the right. Or just detect that my browser locale is not en_US, and show Celsius...

Minor thing: metres per second (m/s) is a fairly common wind measurement unit. And it should be km/h, not KPH.

https://championtraveler.com/dates/best-time-to-visit-copenh...

otterpro
Nice website, as I had always been looking for such travel website like this.

On the travel-weather-map site, I searched for "San Francisco" and the first result was Argentina, and second was Costa Rica. I hope that the result is based on popularity and not based on alphabetical order.

ignostic
The search needs some work :) Sadly it is not popularity-based at all.
Steeeve
I don't know if that Tableau map is going to scale to your desired traffic levels. It's a great enterprise tool, and yeah there are a few publications that leverage it, but my instincts tell me to avoid it on a mid-to-high traffic public page. I could be wrong. It's a difficult graph to replicate under fire, but not so hard that a day or two spent on it wouldn't produce a more performant version.
codingdave
Weather is just one small piece of people's thought process when planning a vacation. But this tool is clearly all about weather... Perhaps finding a new way to describe it other than "the best time to visit" would avoid people coming down on the tool because they want to talk about more than the weather.
cortesoft
Yeah, as someone from Southern California, you don't really need to think about weather when you come visit... maybe a bit of june gloom, but even that isn't bad.
swampthing
This is a great idea, and something I always wished existed - kudos! Seems like there's some great opportunities for SEO and advertising here as well - keep rocking!
nsnick
This tool doesn’t know about winter destinations. Enter Salt Lake City or Denver.
madman2890
I'm stoked you built this, as I've had the idea and desired the platform for a while. I do a ton of last minute travel and have semi-unlimited options so it's hard to filter down to the best options that offer what I'm looking for.
lukasm
Time to visit Australia is all year long, but what I hear the best is November or February.
cstrat
I feel Autumn and Spring are the best times to visit Sydney.

During the Summer you could travel around the southern parts (Tasmania and SA). In the winter months you can spend time in Cairns (anywhere up north really) and its beautiful. You actually don't want to be up north during summer, it is too hot and it's stinger season in the ocean.

corybrown
This is cool, where do you get the data? I see its from NOAA, but what kind of data files do you get from them?
fwx
This is very cool. Long shot but any chance you can blog about the algorithm used? Or open source the same?
ignostic
I'm not sure many people would be interested, but I'd have no problem doing a write up with the relevant source. I'll try to get to it next week after fixing all these bugs people are finding.
tmaly
I like this idea a lot, but there is also on thing to consider, Crowds. The best weather also draws the biggest crowds. This drives up food and hotel prices. If you could somehow factor in the crowds and peak season, you could have a really useful tool.