Irish Grand National Supercomputer Prediction

In consultation with the domain experts, the features were assigned different weightages. In the case of missing values for any of these, we used the median from historical data to represent the values.

Categorical features were encoded using LabelEncoder for modelling purposes. Numerical features were scaled using StandardScaler to ensure comparable scales

Determining The ‘Typical Winner’

Using the algorithm mentioned above, we extracted the characteristics of all winning horses at the Irish Grand National, to determine the characteristics of a ‘typical winning horse’ at the race.

Once they were extracted, we used the median values as a representation of the characteristics of a typical winner.

From our analysis, these are the characteristics of a winning horse at the event:

Assigning Similarity Scores

With comprehensive numerical information on the characteristics of a winning horse ready, the next step was to find which horses from the competing field in 2025 come closest to a typical winner.

We extracted the relevant data for all horses competing in the 2025 Irish Grand National and then assigned similarity scores. The closer the similarity score to 1, the higher the winning probability of the particular horse.

And The Predicted Winner Is...

Using our extensive analysis, the supercomputer predicts Now Is The Hour to win the 2025 Irish Grand National. The horse has a similarity score of 0.9986 to a typical winner, which gives the Gavin Cromwell-trained runner the closest match to the characteristics of an average winner of the race and accordingly equates to a 95% chance of contending.

Now Is The Hour won his Maiden Hurdle at Fairyhouse in January 2024 and arrives back to the racecourse following a highly promising performance at the Cheltenham Festival where he was running in second place in the National Hunt Chase when falling at the penultimate fence.

The second favourite as per our analysis is Jonnywho, trained by Jonjo and A J O’Neill. The British-trained horse has a similarity score 0.9985 which puts it a hair’s breadth behind Now Is The Hour. Accordingly, the probability for Jonnywho contending is at 94.996 percent, making it a very close second choice.

Intense Raffles, the defending champion, isn’t heavily favoured by our supercomputer, with a probability of 91.125 percent. The winner of the 2025 Grand National, Nick Rockett, has only been given a probability score of 51.813 percent and I Am Maximus, who won the Irish Grand National in 2023 and the Aintree Grand National in 2024, has only been given a probability of 45.137 percent.

It is important to note that we capped the maximum chance of contenting to 95 percent so as to account for a level of uncertainty. Similarly, the minimum threshold was put to five percent.

Methodology